I like the coefienti in front of 2nd degree to be positive
times -1
x^2-4x=-x+4
add x to both sides and minus 4 from both sides
x^2-3x-4=0
factor
what 2 numbers multiply to get -4 and add to get -3?
-4 and 1
(x-4)(x+1)=0
set to zero
x-4=0
x=4
x+1=0
x=-1
-1 and 4
C is answer
