SOlve x + 4y = 28 and 5x - 4y = - 28

x + 4y = 28

x + 4y-4y = 28-4y

x=28-4y

5x - 4y = - 28

5(28-4y) - 4y = - 28

5(28) (5)(-4y) - 4y = - 28

140-20y-4y=-28

140-24y=-28

140-24y-140=-28-140

-24y=-168

-24y/-24=-168/-24

y=7

x=28-4y

x=28-4(7)

x=28-28

x=0