Algebra is a branch of mathematics that uses symbols and letters to represent numbers and quantities. It is a powerful tool that can be used to solve a wide range of problems, from simple arithmetic to complex scientific and engineering equations.

This article provides a comprehensive guide to algebra problems, with answers. It covers a wide range of topics, from basic equations to more complex problems involving variables, exponents, and polynomials.

**Solving Linear Equations**

Linear equations are equations of the form $ax + b = c$, where $a$, $b$, and $c$ are constants and $x$ is the variable. To solve a linear equation, we can use the following steps:

- Subtract $b$ from both sides of the equation to get $ax = c – b$.
- Divide both sides of the equation by $a$ to get $x = \frac{c – b}{a}$.

**Example:** Solve the equation $2x + 5 = 13$.

**Solution:**

- Subtract 5 from both sides of the equation to get $2x = 8$.
- Divide both sides of the equation by 2 to get $x = 4$.

Therefore, the solution to the equation $2x + 5 = 13$ is $x = 4$.

**Solving Quadratic Equations**

Quadratic equations are equations of the form $ax^2 + bx + c = 0$, where $a$, $b$, and $c$ are constants and $x$ is the variable. To solve a quadratic equation, we can use the following steps:

- Factor the quadratic equation into the form $(x + d)(x + e) = 0$.
- Set each factor equal to zero and solve for $x$.

**Example:** Solve the equation $x^2 + 6x + 9 = 0$.

**Solution:**

- Factor the quadratic equation to get $(x + 3)(x + 3) = 0$.
- Set each factor equal to zero and solve for $x$:

$x + 3 = 0$ $x = -3$

Therefore, the solutions to the equation $x^2 + 6x + 9 = 0$ are $x = -3$ and $x = -3$.

**Solving More Complex Equations**

In addition to linear and quadratic equations, algebra also covers more complex equations involving variables, exponents, and polynomials. To solve these types of equations, we often need to use a combination of different techniques, such as factoring, substitution, and elimination.

**Example:** Solve the equation $\frac{x}{2} + \frac{3}{x} = 5$.

**Solution:**

- Multiply both sides of the equation by $2x$ to get $x + 6 = 10x$.
- Subtract $x$ from both sides of the equation to get $6 = 9x$.
- Divide both sides of the equation by 9 to get $\frac{2}{3} = x$.

Therefore, the solution to the equation $\frac{x}{2} + \frac{3}{x} = 5$ is $x = \frac{2}{3}$.

**Conclusion**

This article has provided a comprehensive guide to algebra problems, with answers. It has covered a wide range of topics, from basic equations to more complex problems involving variables, exponents, and polynomials.

**FAQs**

**Q.What is the difference between an equation and an expression?**

An equation is a statement that two expressions are equal. An expression is a mathematical combination of numbers, variables, and operators.

**Q.What is the difference between a linear equation and a quadratic equation?**

A linear equation is an equation of the form $ax + b = c$, where $a$, $b$, and $c$ are constants and $x$ is the variable. A quadratic equation is an equation of the form $ax^2 + bx + c = 0$, where $a$, $b$, and $c$ are constants and $x$ is the variable.

**Q.How do I solve a system of equations?**

A system of equations is a set of two or more equations that have the same variables. To solve a system of equations, we can use a variety of methods, such as elimination, substitution, and graphing.

**Q.What are some common algebra mistakes?**

Some common algebra mistakes include:

- Forgetting to add or subtract the same constant to both sides of an equation
- Dividing by zero
- Assuming that $x^2 = x$
- Not factoring a quadratic equation before using the quadratic formula

**Solving Linear Inequalities**

A linear inequality is an inequality of the form $ax + b < c$, $ax + b > c$, $ax + b \leq c$, or $ax + b \geq c$, where $a$, $b$, and $c$ are constants and $x$ is the variable. To solve a linear inequality, we can use the following steps:

- Isolate $x$ on one side of the inequality.
- Determine the sign of the coefficient of $x$.
- If the coefficient is positive, then the solution to the inequality is all values of $x$ that make the right-hand side of the inequality greater than or equal to the left-hand side.
- If the coefficient is negative, then the solution to the inequality is all values of $x$ that make the right-hand side of the inequality less than or equal to the left-hand side.

**Example:** Solve the inequality $2x + 5 < 13$.

**Solution:**

- Isolate $x$ on one side of the inequality:

```
2x + 5 < 13
2x < 13 - 5
2x < 8
x < 4
```

- Determine the sign of the coefficient of $x$ in the inequality:

```
2x < 4
```

The coefficient of $x$ is 2, which is positive.

- If the coefficient is positive, then the solution to the inequality is all values of $x$ that make the right-hand side of the inequality greater than or equal to the left-hand side:

```
x < 4
```

Therefore, the solution to the inequality $2x + 5 < 13$ is all values of $x$ less than 4.

**Solving Quadratic Inequalities**

A quadratic inequality is an inequality of the form $ax^2 + bx + c < 0$, $ax^2 + bx + c > 0$, $ax^2 + bx + c \leq 0$, or $ax^2 + bx + c \geq 0$, where $a$, $b$, and $c$ are constants and $x$ is the variable. To solve a quadratic inequality, we can use the following steps:

- Factor the quadratic expression.
- Set each factor equal to zero and solve for the critical points.
- Determine the intervals where the quadratic expression is positive and negative.
- Use the critical points to divide the number line into intervals.
- Evaluate the quadratic expression at a point in each interval to determine whether the expression is positive or negative in that interval.
- Write the solution to the inequality in interval notation.

**Example:** Solve the inequality $x^2 + 6x + 9 < 0$.

**Solution:**

- Factor the quadratic expression:

```
x^2 + 6x + 9 = (x + 3)(x + 3) < 0
```

- Set each factor equal to zero and solve for the critical points:

```
x + 3 = 0
x = -3
```

- Determine the intervals where the quadratic expression is positive and negative:

```
x < -3 x > -3
```

- Use the critical points to divide the number line into intervals:

```
(-\infty, -3) (-3, \infty)
```

- Evaluate the quadratic expression at a point in each interval to determine whether the expression is positive or negative in that interval:

```
x = -4
(-4)^2 + 6(-4) + 9 = 1 < 0
x = -2
(-2)^2 + 6(-2) + 9 = 1 > 0
```

- Write the solution to the inequality in interval notation:

```
(-\infty, -3)
```

Therefore, the solution to the inequality $x^2 + 6x + 9 < 0$ is all values of $x$ less than -3.

**Solving More Complex Equations and Inequalities**

In addition to linear and quadratic equations and inequalities, algebra also covers more complex equations and inequalities involving variables, exponents, and polynomials. To solve these types of problems, we often need to use a combination of different techniques, such as factoring, substitution, elimination, and graphing.

**Solving Systems of Equations**

A system of equations is a set of two or more equations that have the same variables. To solve a system of equations, we can use a variety of methods, such as elimination, substitution, and graphing.

**Elimination**

The elimination method is a straightforward way to solve a system of equations. To use this method, we add or subtract the equations in the system so that one of the variables cancels out. We can then solve for the remaining variable and substitute this value into one of the original equations to solve for the other variable.

**Example:** Solve the system of equations:

```
x + 2y = 5
2x - y = 1
```

**Solution:**

```
-2x + y = -1
x + 2y = 5
```

Adding the two equations together, we get:

```
3y = 4
```

Dividing both sides by 3, we get:

```
y = \frac{4}{3}
```

Substituting this value into the first equation, we get:

```
x + 2(4/3) = 5
```

```
x + 8/3 = 5
```

```
x = 1/3
```

Therefore, the solution to the system of equations is $x = \frac{1}{3}$ and $y = \frac{4}{3}$.

**Substitution**

The substitution method is another straightforward way to solve a system of equations. To use this method, we solve one of the equations for one of the variables and substitute this value into the other equation. We can then solve for the remaining variable.

**Example:** Solve the system of equations:

```
x + 2y = 5
2x - y = 1
```

**Solution:**

Solving the first equation for $x$, we get:

```
x = 5 - 2y
```

Substituting this value into the second equation, we get:

```
2(5 - 2y) - y = 1
```

```
10 - 4y - y = 1
```

```
-5y = -9
```

```
y = \frac{9}{5}
```

Substituting this value into the first equation, we get:

```
x + 2(9/5) = 5
```

```
x + 18/5 = 5
```

```
x = 1/5
```

Therefore, the solution to the system of equations is $x = \frac{1}{5}$ and $y = \frac{9}{5}$.

**Graphing**

The graphing method is a visual way to solve a system of equations. To use this method, we graph both equations on the same coordinate plane. The solution to the system of equations is the point where the two lines intersect.

**Example:** Solve the system of equations:

```
x + 2y = 5
2x - y = 1
```

**Solution:**

Graphing the first equation, we get:

```
y = -(x/2) + 5/2
```

Graphing the second equation, we get:

```
y = 2x - 1
```

The two lines intersect at the point $(1,3)$. Therefore, the solution to the system of equations is $x = 1$ and $y = 3$.

**Conclusion**

This article has provided a comprehensive guide to algebra problems, with answers. It has covered a wide range of topics, from basic equations and inequalities to more complex problems involving variables, exponents, and polynomials. It has also covered how to solve systems of equations using the elimination, substitution, and graphing methods.