93.2k views
2 votes
The sum of 3 times a number and 4 is between -8 and 10. Define a variable, write an inequality, and solve the problem.

2 Answers

2 votes

Final answer:

The solution to the inequality where the sum of 3 times a number and 4 is between -8 and 10 is that the number, represented by the variable x, must be greater than -4 and less than 2. The inequality is -4 < x < 2.

Step-by-step explanation:

To solve the problem where the sum of 3 times a number and 4 is between -8 and 10, we start by defining a variable to represent the unknown number. Let's define the variable x to represent the number.

Given this variable, we can write the inequality as:

-8 < 3x + 4 < 10

We now need to solve this compound inequality, which is essentially two inequalities in one:

  1. -8 < 3x + 4
  2. 3x + 4 < 10

First, we subtract 4 from each part of the compound inequality:

  • -8 - 4 < 3x + 4 - 4
  • 3x + 4 - 4 < 10 - 4

Simplifying both inequalities, we get:

  • -12 < 3x
  • 3x < 6

Next, we divide each part by 3 to solve for x:

  • -12 / 3 < 3x / 3
  • 3x / 3 < 6 / 3

After division, the solution is:

  • -4 < x
  • x < 2

Therefore, the solution set for x is -4 < x < 2, meaning the number must be greater than -4 and less than 2.

User Teja Nandamuri
by
8.8k points
5 votes

Understanding:

The sum of 3 times a number (i'll define it as x) and 4 means
3x+4 is between -8 and 10 which means the value of 3x+4 is less than 10 and greater than -8. With that said, the inequality for that problem would be
-8<3x+4<10.

Solving the problem:

Now we know that
-8<3x+4<10, you can solve the problem by subtracting 4 from each side then dividing by 3.


-8-4<3x+4-4<10-4\\-12<3x<6\\(-12)/(3) <(3x)/(3)<(6)/(3)\\-4<x<2

Final Answer:


-4<x<2

The sum of 3 times a number and 4 is between -8 and 10. Define a variable, write an-example-1
User Nick Dixon
by
7.9k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories