Answer:
if y =50 then x = 10 ......... option d
There you go. I assumed you know how to derrivate!
Okay here:
Let L be the length and W the width of the rectangle.
1. w=2•L
2. 2L+2W=36
Substitute eq. 1 into eq. 2,
2L+2•(2•L)=36
2L+4L=36
6L=36
L=9
Not done yet, then from eq. 1,
W=2•L
W=2•9
W=18 <------- Your answer. :)
