Answer:
x=20
Step-by-step explanation:
I'm pretty sure it is d, you are combining the terms which is the same thing.
Answer:21
Step-by-step explanation:
x=length
x(x-6)=315
x^2-6x=315
x^2-6x-315=0
(x-21)(x+15)
x=21, x=-15
x cannot be negative so the only answer is 21
