Question

1) - Phan tich cac da thuc sau thanh nhan tu :

a) 14x²y² - 21xy² + 28x²y d) 2 phan 7 x(3y -1 )-2 phan 7y (3y-1)

b) x³ -3x² + 3x- 1 e) (x+y)²-4x²

c) 27x²+1phan 8 f) (x+y)³-(x-y)³

2) tim x biet

a) x²(x+1)+2x(x+1)=0 b) x(3x-2)-5(2-3x)=0

c) 4 phan 9 -25x²=0 d) x²-x+phan4=0

3) tinh nhanh cac gia tri bieu thuc sau :

a) 17.91,5+170.0,85 b) 2016²-16²

c) x(x-10-y(1-x)tai x=2001va y = 2999

Answer 1

2.a là x=0 , x=-1, x=-2
2.b là x=2/3 , x=-5