x=y+3 -5x-4y=30 ------------------- Substitute y + 3 for x in -5x-4y=30 -5(y+3)-4y=30 -9y-15=30 ---------------------------- Add 15 to each side -9y-15+15=30+15 -9y = 45 ----------------------------------- Divide each side by -9 -9y ÷ -9 = 45 ÷ -9 y = -5 Now we solve for x ==================================================================== Substitute -5 for y in x = y + 3 x=-5+3 x = -2 ---------------------- (-2,-5) is your answer
