Do you mean this number:

?
The we have to simplify the fraction part, since the nominator is bigger than the denominator.
How many denominators fit into the nominator? 20: 4=5
5! so

is simply 5 and we can add it to the main number:
175+5=180
Judging on the question I figured that the perpendicular line's slope would be -x since the slope of a perpendicular line is opposite to that of a the reference line.
Thus, your answer should be y=-x+4 considering that is the only equation with the slope of -x.
X= -2-x+6
2x=4
x=2
y=-2-2
y=-4
X= 1,-3 If you factor equation you get x-1=0 and x+3=0