mwtode substitusi dari y=x+7dan 4x+3y=-7

Y = x + 7

4x + 3y = -7
4x + 3(x+7) = -7
4x + 3x + 21 = -7
7x + 21 = -7
7x = (-7) - (-21)
7x = -7 + 21
7x = 14
x = 2

y = x +7
y = 2 + 7
y = 9