Question

What value of x is in the solution set of –5x – 15 > 10 + 20x?

Answer 1

-5x - 15 > 10 + 20x / + 15
-5x > 25 + 20x / - 20x
-25x > 25 / ÷ ( -25 )
x < - 1

Answer 2

–5x – 15 > 10 + 20x

Add 5x to both sides:

-15 > 10 + 25x

Subtract 10 from both sides:

-25 > 25x

Divide both sides by 25

-1 > x

Switch sides:

x < -1

Answer: x < -1