or
Don't have an account? Register
x-1x2-x-20+4-xx2-4x-5 = x-1x2-5x+4x-20 + 4-xx2 -5x +x-5 = x-1x x-5+ 4 x-5 + 4 -xx x-5 +1 x-5 = x-1x-5 x+4 + 4-xx-5 x+1 = x-5 x+1 + 4-x x+4x-5 x+4 x+1 = x-1 x+1 +4+x 4-x x-5 x+4 x+1 = x2 - 1 + 42 - x2x-5 x+4 x+1 = x2 -1 + 16 - x2x-5 x+4 x+1 = 15x-5 x+4 x+1
.