WAEC - Mathematics (2007 - No. 48)
Which of the following is a factor of 2 - x - x2?
1 - x
1 + x
x - 1
2 - x
Giải thích
2 - x - x2; (2 - 2x) + (x - x2)
= 2(1 - x) + x(1 - x)
= (1 - x)(2 + x)
= 1 - x
= 2(1 - x) + x(1 - x)
= (1 - x)(2 + x)
= 1 - x