15
Simultaneous Equations. 4x + 5y = 51 4x - 5y = 21 eliminate 'y' by addition. Hence 8x = 72 x = 72/8 x = 9 When x = 9 Substitute into eith equation. 4(9) + 5y = 51 36 + 5y = 51 5y = 51 - 36 5y = 15 y = 3 Hence the answer is ( x,y) = ( 9,3).
5y=25x 25x=5y -5y 25x-5y=0
If: 4x = 5y Then: x = 5y/4
(-5, 2)
If: 5y = 4735 Then: y = 947
7
5y + 7 = 25y = -5y = -1
y = -6
x = (-5y + 4) / 7
15
8 - 5y = 12 -5y = 4 y = -4/5
x = 0 and y = 4