solve the system of linear equations

x + y = 4 and 2x + 3y = 0

solve this answer by using substitution. set the first equation to x=-y+4 then substitute - y+4 for x in the second equation.

2 (-y+4) + 3y=0

-2y+8 + 3y=0

y+8=0

y=-8

now use - 8 and solve for x

x + (-8) = 4

x=12