Inequalities are the "outliers" of equations and many of the rules that apply to equations also apply to inequalities.
In terms of writing, the main difference is that instead of the equal sign "=" "=" , we use greater than ">" ">" or less than "<" "<" signs. 

Inequalities can be simple or more complex and also contain fractions, parentheses, and more. 

Another thing that distinguishes inequalities from equations is that equations with one variable have a unique solution. On the contrary, inequalities have a range of solutions. 

Inequalities between linear functions will translate into questions like when F(x)>G(x) F\left(x\right)>G\left(x\right) or vice versa.
We can answer this type of questions in two ways:

  • Using equations
    if the equations of the two functions are given, we will place them in the inequality, solve it, and find the corresponding X X values.
  • Using graphs
    we will examine at what X X values, Y Y values of the function in question are higher or lower than the function in the inequality.

Mathematical inequality symbols explained: X > Y (greater than), X < Y (less than), X ≥ Y (greater than or equal to), and X ≤ Y (less than or equal to).

Practice Inequalities

Examples with solutions for Inequalities

Exercise #1

Solve the inequality:


7+2x<15 7 + 2x < 15

Step-by-Step Solution

To solve the inequality 7+2x<15 7 + 2x < 15 , we start by isolating the variable x x .

First, subtract 7 from both sides of the inequality:

7+2x7<157 7 + 2x - 7 < 15 - 7

Simplifying this, we get:

2x<8 2x < 8

Next, divide both sides by 2 to solve for x x :

2x2<82 \frac{2x}{2} < \frac{8}{2}

Thus, the solution is:

x<4 x < 4

Answer

x < 4

Exercise #2

Solve the following inequality:

5x+8<9

Video Solution

Step-by-Step Solution

This is an inequality problem. The inequality is actually an exercise we solve in a completely normal way, except in the case that we multiply or divide by negative.

Let's start by moving the sections:

5X+8<9

5X<9-8

5X<1

We divide by 5:

X<1/5

And this is the solution!

 

Answer

x<\frac{1}{5}

Exercise #3

Solve the inequality:


5-3x>-10

Video Solution

Step-by-Step Solution

Inequality equations will be solved like a regular equation, except for one rule:

If we multiply the entire equation by a negative, we will reverse the inequality sign.

 

We start by moving the sections, so that one side has the variables and the other does not:

-3x>-10-5

-3x>-15

Divide by 3

-x>-5

Divide by negative 1 (to get rid of the negative) and remember to reverse the sign of the equation.

x<5

Answer

5 > x

Exercise #4

Solve the following inequality:

3x+410 3x+4 \leq 10

Step-by-Step Solution

To solve the inequality 3x+410 3x+4 \leq 10 , follow these steps:

1. Subtract 4 from both sides: 3x6 3x \leq 6 .

2. Divide both sides by 3: x2 x \leq 2 .

Answer

x2 x \leq 2

Exercise #5

Solve the following inequality:

2x5>3 2x-5 > 3

Step-by-Step Solution

To solve the inequality 2x5>3 2x-5 > 3 , follow these steps:

1. Add 5 to both sides: 2x>8 2x > 8 .

2. Divide both sides by 2: x>4 x > 4 .

Answer

x>4 x > 4

Exercise #6

Solve the following inequality:

4x+311 4x+3 \geq 11

Step-by-Step Solution

To solve the inequality 4x+311 4x+3 \geq 11 , follow these steps:

1. Subtract 3 from both sides: 4x8 4x \geq 8 .

2. Divide both sides by 4: x2 x \geq 2 .

Answer

x2 x \geq 2

Exercise #7

Solve the following inequality:

6x2<4 6x - 2 < 4

Step-by-Step Solution

To solve the inequality 6x2<4 6x - 2 < 4 , follow these steps:

1. Add 2 to both sides: 6x<6 6x < 6 .

2. Divide both sides by 6: x<1 x < 1 .

Answer

x<1 x < 1

Exercise #8

Solve the inequality:

4x + 7 > 19

Step-by-Step Solution

To solve the inequality 4x+7>19 4x + 7 > 19 , follow these steps:

1. Subtract 7 from both sides to isolate the term with x x on one side.

4x+77>197 4x + 7 - 7 > 19 - 7

2. This simplifies to:

4x>12 4x > 12

3. Next, divide each side by 4 to solve for x x .

x>124 x > \frac{12}{4}

4. This simplifies further:

x>3 x > 3

Therefore, the solution is x>3 x > 3 .

Answer

x>3 x > 3

Exercise #9

Solve the inequality:


2x+93 -2x + 9 \leq 3

Step-by-Step Solution

To solve the inequality 2x+93 -2x + 9 \leq 3 , follow these steps:

1. Subtract 9 from both sides:

2x+9939 -2x + 9 - 9 \leq 3 - 9

2. This simplifies to:

2x6 -2x \leq -6

3. Divide each side by -2, remembering to reverse the inequality sign since dividing by a negative number:

x62 x \geq \frac{-6}{-2}

4. Simplifying gives:

x3 x \geq 3

Thus, the solution is x3 x \leq 3 .

Answer

x3 x \geq 3

Exercise #10

Solve the inequality:

6x - 4 < 14

Step-by-Step Solution

To solve the inequality 6x4<14 6x - 4 < 14 , follow these steps:

1. Add 4 to both sides:

6x4+4<14+4 6x - 4 + 4 < 14 + 4

2. Simplify:

6x<18 6x < 18

3. Divide both sides by 6 to solve for x x :

x<186 x < \frac{18}{6}

4. This simplifies to:

x<3 x < 3

Thus, the solution is x<3 x < 3 .

Answer

x < \frac{9}{3}

Exercise #11

Which diagram represents the solution to the inequality below?

5-8x<7x+3

Video Solution

Step-by-Step Solution

First, we will move the elements:

5-8x>7x+3

5-3>7x+8x
2>15x

We divide the answer by 13, and we get:

x > \frac{2}{15}

Answer

Exercise #12

What is the solution to the inequality shown in the diagram?

-43

Video Solution

Step-by-Step Solution

The task is to interpret the inequality shown by a number line diagram.

First, observe the number line diagram provided. The numbers -4 and 3 are highlighted with vertical dashed lines. A critical point is at 3, where the circle is filled, indicating the inclusion of this point in the set. The line then extends from 3 to the right, suggesting that any point greater than or equal to 3 is included.

This indicates the inequality for x x is x3 x \geq 3 . The filled circle means 3 itself is part of the solution.

Thus, the solution to the inequality represented by the diagram is:

3x 3 \leq x

This matches with choice number 3 in the provided options: 3x 3 ≤ x .

Answer

3x 3 ≤ x

Exercise #13

What is the solution to the following inequality?

10x43x8 10x-4≤-3x-8

Video Solution

Step-by-Step Solution

In the exercise, we have an inequality equation.

We treat the inequality as an equation with the sign -=,

And we only refer to it if we need to multiply or divide by 0.

 10x43x8 10x-4 ≤ -3x-8

We start by organizing the sections:

10x+3x48 10x+3x-4 ≤ -8

13x48 13x-4 ≤ -8

13x4 13x ≤ -4

Divide by 13 to isolate the X

x413 x≤-\frac{4}{13}

Let's look again at the options we were asked about:

Answer A is with different data and therefore was rejected.

Answer C shows a case where X is greater than413 -\frac{4}{13} , although we know it is small, so it is rejected.

Answer D shows a case (according to the white circle) where X is not equal to413 -\frac{4}{13} , and only smaller than it. We know it must be large and equal, so this answer is rejected.

 

Therefore, answer B is the correct one!

Answer

Exercise #14

Which inequality is represented by the numerical axis below?

-7-20

Video Solution

Step-by-Step Solution

To solve the problem and determine the inequality represented by the number line, follow these steps:

  • Examine the endpoints of the interval on the number line. At 7-7, there is an open circle, indicating that 7-7 is not included in the interval.
  • At 00, there is a closed circle, indicating that 00 is included in the interval.
  • This gives us the inequality for the interval: open at 7-7 (<<) and closed at 00 (\leq).

Therefore, the inequality represented by the number line is 7<x0 -7 < x \leq 0 .

This is consistent with option 1 in the provided choices. The inequality is represented by 7<x0-7 < x \leq 0.

Answer

-7 < x ≤2

Exercise #15

Solve the inequality:

5x+b > 2x+3

Step-by-Step Solution

To solve the inequality 5x+b > 2x+3 , we will follow these steps:

  • Subtract 2x 2x from both sides: 3x + b > 3

  • Subtract b b from both sides: 3x > 3 - b

  • Divide both sides by 3 3 : x > -\frac{1}{3}b + 1

Answer

x > -\frac{1}{3}b+1