Conceptually, you are asking for the additive inverse of 8. By definition, in fact, the additive inverse of a number 
is a number 
such that 
You obtain the additive inverse of a number by switching its sign, so the additive inverse of 8 is -8. In fact, you have
Answer: -10
Step-by-step explanation:
Simplifying
-3(y + 5) = 15
Reorder the terms:
-3(5 + y) = 15
(5 * -3 + y * -3) = 15
(-15 + -3y) = 15
Solving
-15 + -3y = 15
Solving for variable 'y'.
Move all terms containing y to the left, all other terms to the right.
Add '15' to each side of the equation.
-15 + 15 + -3y = 15 + 15
Combine like terms: -15 + 15 = 0
0 + -3y = 15 + 15
-3y = 15 + 15
Combine like terms: 15 + 15 = 30
-3y = 30
Divide each side by '-3'.
y = -10
Simplifying
Multiply then add and then subtract
3/5 is in its simplest form, but as a decimal it’s 0.6
21 - 13.50= 7.50
so based on what your question is asking, Serena makes $7.50 more than Gabe per hour.
