Question

câu 1 b) (2x²-3).(x+5)               câu 2 a) (x+3)²            b) y²-25         câu 3 a) 2x²+2xy+3x+3y     b) x²-25-2xy+y²     câu 4 a) 6x³y²z : 2x³y     b) (4x³y⁴+3x²y²-2xy):2xy      câu 5 a) 64²-36²      b) M=(x-y).(x+y)-3x.(x+2y)+2x²y²     tại x=1 phần 6 ; y = 2010

 

Answer 1

Câu 1:

$(2x^2-3)(x+5)=2x^2(x+5)-3(x+5)=2x^3+10x^2-3x-15$

 

Answer 2

Câu 2:

a.

$(x+3)^2=x^2+2.x.3+3^2=x^2+6x+9$

b.

$y^2-25=y^2-25$
 

Answer 3

Câu 3:

a.

$2x^2+2xy+3x+3y=(2x^2+2xy)+(3x+3y)=2x(x+y)+3(x+y)=(x+y)(2x+3)$

b.

$x^2-25-2xy+y^2=(x^2-2xy+y^2)-25=(x-y)^2-5^2=(x-y-5)(x-y+5)$

Answer 4

Câu 4:
a.

$6x^3y^2z:(2x^3y)=(6:2)(x^3:x^3)(y^2:y)z=3yz$

b.

$(4x^3y^4+3x^2y^2-2xy):(2xy)=\frac{4x^3y^4}{2xy}+\frac{3x^2y^2}{2xy}-\frac{2xy}{2xy}=2x^2y^3+1,5xy-1$

Answer 5

Câu 5:

a. $64^2-36^2=(64-36)(64+36)=28.100=2800$

b. $M=(x-y)(x+y)-3x(x+2y)+2x^2y^2$

$=x^2-y^2-3x^2-6xy+2x^2y^2=-2x^2-y^2-6xy+2x^2y^2$

$=-2.(\frac{1}{6})^2-2010^2-6.\frac{1}{6}.2010+2(\frac{1}{6})^2.2010^2=-3817660,056$