WAEC - Mathematics (1998 - No. 14)
Solve the equation 5x2 - 4x - 1 = 0
-1, 1/5
-1, -1/5
1, 1/5
1, -1/5
-1, 5
คำอธิบาย
5x2 - 4x - 1 = 0
5x2 5x + x -1 = 0
5x(x - 1) + (x - 1) = 0
(5x + 1)(x -1) = 0
x = -1/5 or 1 = 0
5x2 5x + x -1 = 0
5x(x - 1) + (x - 1) = 0
(5x + 1)(x -1) = 0
x = -1/5 or 1 = 0