Answer:
both problems are proportional
Answer:
or 
Step-by-step explanation:
we have

step 1
Group terms that contain the same variable

step 2
Combine like terms

step 3
Eliminate parenthesis

step 4
Factor the number 

Since x is the length, then x+7 has to be the width.
The area of a rectangle can be found via the formula :
A = length * width
So if we replace the area with the given number (170) and the length, and width, with what we assumed, we get..
170 = x * (x+7)
[which is.. ]
170 = x^2 +7x
0 = x^2 +7x - 170
And that is the answer.