Question

3x+8=3x+____

Which value could you write in the blank above that would make the equation have one solution?
a.2x


b.8


c.7

Answer 1

2x

Explanation:

Think about it. Adding 8 would make the equation: 3x+8=3x+8. That has infinite solutions. if you made it 7, it would be 3x+8=3x+7, which is impossible.

Therefore, it must be 2x, which would make the equation 3x+8=5x.

Let's check: 3x+8=5x

8=2x

4=x

All good.