You would use the equation
F+V=E+2
Step-by-step explanation:
If we let the width be w, then the length is w+3.5.
This means that w(w+3.5)=11
w^2 + 3.5w - 11 = 0
2w^2 + 7w - 22 = 0 (multiply both sides by 2)
(2w+11)(w-2)=0
w = -11/2 or w = 2 (disregard w = -11/2 as distance is positive)
This means that w=2, and thus the length is 2+3.5=5.5
F(x) = kx
12 = 8k
k = 12/8 = 3/2
Required equation is f(x) = 3/2 x
3/(5x) + x = 3/(5x) + x/1 * (5x)/(5x)
= 3/(5x) + 5x²/5x
= (3+5x²) / 5x