i dont know how to do this could someone help

Answer:
17, 5
Step-by-step explanation:
Let the width be x
width = x
length = x + 12
length x width = x(x + 12)
length x width = x² + 12x
x² + 12x = 85
x² + 12x - 85 = 0
Now it is just a quadratic:
The 2 numbers we need are 17 and -5
(x + 17)(x - 5) = 0
x = -17 or x = 5.
Since width and length cannot be negative, x must equal 5.
Width = 5
length = 17
The answer is 17, 5.
We are given two things :
We can represent the length and width as x + 12 and x respectively.
Now, the formula for the area of a rectangle is :
Area = Length x width
Now, let's substitute the values for length and width in the formula along with the area.
We now have a quadratic equation, which can either be solved by splitting the middle term, or by using the quadratic formula. For convenience purposes, we'll go with the first one.