Answer:
The answer is D
Step-by-step explanation:

5(5x-10)=15
5x-10=3
5x=10+3
5x=13
Divide both sides by 5-5 and 5 cancel out to leave you with x 13/5 =2.6
X=2.6
They're opposite numbers.
C. 3x + 7 because you can factor out the other 3.
a. 16+4x=4(4+X)
b. 25x+30y=5(5x+6y)
d. 40x-30y = 5(8x-6y)
hope this helps!