spite of a lot of people around, we managed to talk seriously

the heavy bag, she managed to carry it herself

of his mother's refusion

not being very nice, the car serves its purpose

spite of not having much money, he wants to buy a car

Bài 10:

a: \(\left(x^2+4x+8\right)^2+3x^{}\left(x^2+4x+8\right)+2x^2\)

\(=\left(x^2+4x+8\right)^2+2x\left(x^2+4x+8\right)+\left(x^2+x+8\right)x+2x^2\)

\(=\left(x^2+4x+8+2x\right)\left(x^2+4x+8+x\right)\)

\(=\left(x+4\right)\left(x+2\right)\left(x^2+5x+8\right)\)

b: abc-(ab+ac+bc)+(a+b+c)-1

=abc-ab-ac-bc+a+b+c-1

=ab(c-1)-a(c-1)-b(c-1)+(c-1)

=(c-1)(ab-a-b+1)

=(c-1)(b-1)(a-1)

Bài 8:

a: \(x^4+4\)

\(=x^4+4x^2+4-4x^2\)

\(=\left(x^2+2\right)^2-\left(2x\right)^2=\left(x^2+2+2x\right)\left(x^2+2-2x\right)\)

b: \(4x^8+1=4x^8+4x^4+1-4x^4\)

\(=\left(2x^4+1\right)^2-\left(2x^2\right)^2\)

\(=\left(2x^4+1-2x^2\right)\left(2x^4+1+2x^2\right)\)

c: \(81x^4+4\)

\(=81x^4+36x^2+4-36x^2\)

\(=\left(9x^2+2\right)^2-\left(6x\right)^2\)

\(=\left(9x^2+2-6x\right)\left(9x^2+2+6x\right)\)

d: \(64x^4+y^4\)

\(=64x^4+16x^2y^2+y^4-16x^2y^2\)

\(=\left(8x^2+y^2\right)^2-\left(4xy\right)^2\)

\(=\left(8x^2+y^2-4xy\right)\left(8x^2+y^2+4xy\right)\)

e: \(\left(x^2-8\right)^2+36\)

\(=x^2-16x^2+64+36\)

\(=x^2+20x^2+100-36x^2\)

\(=\left(x^2+10\right)^2-\left(6x\right)^2\)

\(=\left(x^2+10-6x\right)\left(x^2+10+6x\right)\)

f: \(\left(2x^2-4\right)_{}^2+9\)

\(=4x^4-16x^2+16+9\)

\(=4x^4-16x^2+25\)

\(=4x^4+20x^2+25-36x^2\)

\(=\left(2x^2+5\right)^2-\left(6x\right)^2=\left(2x^2+5-6x\right)\left(2x^2+5+6x\right)\)

1 A

2 A

3 C

4 B

5 C

6 D

7 A

8 B

9 D

10 C

3,A

4,D

5,A

6,A

7.C

8.B

9,B

10,B

1 B

2 C

3 A

4 C

5 A

6 A

7 D

8 A

9 B

10 C