y=x^2-5
y=2x-5
y+5=2x
x=(y+5)/2
y=((y+5)/2)^2-5
y=(y^2+10y+25)/4-5
4y=y^2+10y+25-20
0=y^2+6y+5
0=(y+5)(y+1)
y= -5 or -1
y=2x-5 (y= -5 doesn't work for this one so use -1)
-1=2x-5
2x=4
x=2
Using these answers, you can choose answer D with reasonable certainty.