WAEC - Mathematics (2006 - No. 15)
Given that (2x - 1)(x + 5) = 2x2 - mx - 5, what is the value of m
11
5
-9
-10
คำอธิบาย
(2x - 1)(x + 5) = 2x2 - mx - 5
2x2 + 10x - x - 5
= 2x2 + 9x - 5 = 2x2 - mx - 5
comparing the co-efficient of x
-m = 9
m = -9
2x2 + 10x - x - 5
= 2x2 + 9x - 5 = 2x2 - mx - 5
comparing the co-efficient of x
-m = 9
m = -9