WAEC - Mathematics (2015 - No. 12)
Ada draws the graph of y = x2 - x - 2 and y = 2x - 1 on the same axes. Which of these equations is she solving?
x2 - x - 3 = 0
x2 - 3x - 1 = 0
x2 - 3x - 3 = 0
x2 + 3x - 1 = 0
คำอธิบาย
Given; y = x2 - x - 2, y = 2x - 1
Using y = y, gives
x2 - x - 2 = 2x - 1
x2 - 3x - 2 + 1 = 0
therefore, x2 - 3x - 1 = 0
Using y = y, gives
x2 - x - 2 = 2x - 1
x2 - 3x - 2 + 1 = 0
therefore, x2 - 3x - 1 = 0