There is only one solution.
y = x+2
x = -1
Substitute x = -1 in y = x+2
y=-1+2
y = 1
We only get the single value of y and x so It's clear that there's only one solution.
A) Total cost of materials: 145.86 + 52.91 + 17.63 = $216.40
b) Percent cost of hardware: 17.63/216.40 = 0.081
c) Percent cost paint and hardware: (17.63 + 52.91)/216.40 = 0.326
You need to convert it into a whole number