Question

Which number is NOT in the solution set of x + 5 > 10?

A) 4
B) 6
C) 8
D) 12

Answer 1

x = 4 is not in the solution set of the given inequality.

Explanation:

One can try the four suggested answers in the actual inequality, but it is easier to first reduce the inequality solving for "x" (leaving "x" by itself on onw side of the inequality sign), and then have an idea of which values are allowed:

Solve for "x" in the inequality (subtract '5" from both sides:

`x+5>10\\x+5-5>10-5\\x>5`

So we see that the values of "x" that are solutions of the inequality must be strictly larger than 5. And we see that 6,8, and 12 are all larger than 5, but "4" is not.

So x=4 is NOT in the solution set of x+5>10

Answer 2

Option A: 4

Explanation:

x + 5 > 10

x > 10 - 5

x > 5

If x is greater than 5, then x can be 6, 8 and 12, but not 4 as 4 is not up to 5