WAEC - Mathematics (1997 - No. 8)
Solve the equations: 4x -y = 11; 5x + 2y = 4.
x = 6, y = 13
x = -2, y = -3
x = -2, y = 3
x = 2, y = -3
x = 2, y = 3.
คำอธิบาย
4x - y = 11....(1) x 2 8x - 2y = 22....(3)
5x + 12y = 4....(2) x 1 5x + 2y = 4....(4)
add eqn (3) and (4)
13x = 26
x = 2
4(2) - y = 11 \(\implies\) y = 8 - 11
y = -3.