Toán Bài tập đại số 9

C

chuayeu96

giup ban be giai bai tap 61 62 ttrong sach bai tap

co j nho cam on mjnh nhe dung quen cong cua mjnh:khi (69):
bai 61
a, (1-can x)(1+can x+x)= 1^3-(can x )^3
= 1-x can x
b, (can x+2)(x-2can x+4)=(can x)^3+2^3
= x can x+8
c, (can x-can y )(x+y+can xy)= (can x)^3 -(can y)^3
= x canx -y can y
d, (x+can y )(x^2+y-x can y)= x^3+ (can y)^3
= x^3 +y can y
bai 62
a, (4 can x -can 2x )(can x- can 2x)=4x -x can 2-4x can2 +2x:khi (4):
= 6x -5x can 2
=x(6- 5 can 2)
b, (2 can x +can y)(3 can x-2 can y)=6x+3 can xy -4can xy-2y
= 6x-can xy -2y
 
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