Question

Which of the following sets shows all the numbers from the set {0.5,1,2.5,3,3.5} that make the inequality 4a + 2 > 12 true

Answer 1

Two Answers:  3 and 3.5

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Explanation:

Let's isolate the variable 'a' in the given inequality.

4a + 2 > 12

4a + 2-2 > 12-2

4a > 10

4a/4 > 10/4

a > 2.5

In the second step, I subtracted 2 from both sides to undo the "plus 2". In the second to last step, I divided both sides by 4 to undo the multiplication.

The solution is a > 2.5, meaning that anything larger than 2.5 will work in the original inequality.

For example, we could try a = 3 to get

4a + 2 > 12

4*3 + 2 > 12

12 + 2 > 12

14 > 12

which is true. This makes a = 3 a solution. The value a = 3.5 is a similar story, so it's also a solution.

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As an example of a non-solution, let's try a = 1

4a + 2 > 12

4*1 + 2 > 12

4 + 2 > 12

6 > 12

which is false. So we can see why a = 1 is not part of the solution set. You should find that a= 0.5 and a = 2.5 won't work as well for similar reasoning.