Alrighty
remember

means

and

and

for all real values of x
so

means

means

which simplifies to
1=x²+4x-5
minus 1 both sides
0=x²+4x-6
use quadratic formula or complete the square

and

2 solutions
The slope intercept form of that equation would be y = 1/2x + 1. 1 would be the y-intercept, and 1/2 would be the slope. If you are looking for the answers to y and x, you would need another equation containing those variables to figure that out.
I think the answer is 9.375 if it needs to be in decimal form. If it needs to be in fraction form it would be improper, 9 3/8 would be the fraction. Hope it helps!
Answer:
L = w+2
L+w = 60
W+2+w = 60
2w+2 = 60
W+1 = 30
W = 29
L = 31