exam Maths Puzzle Numerical Ability

my question is what i did wrong on this problem?

y=x-4
4x+y=26

Read Solution (Total 0)

exam Other Question

(4x^3-2x^2+x-1) / (x+2) What is the slope of the line with the equation 2x+3y+6=0??
A. (-6,1) B. (-4,-1) C. (-4,3) D. (-2,1) E. (8,1)