b: \(2x^2-7xy+3y^2+x-3y\)

\(=2x^2-6xy-xy+3y^2+x-3y\)

\(=2x\left(x-3y\right)-y\left(x-3y\right)+\left(x-3y\right)\)

\(=\left(x-3y\right)\left(2x-y+1\right)\)

Lời giải:
a.

Đặt $2a^2+5ab-3b^2-7b-2=(a+mb+n)(2a+pb+k)$ với $m,n,p,k$ nguyên 

$\Leftrightarrow 2a^2+5ab-3b^2-7b-2=2a^2+ab(2m+p)+mpb^2+a(k+2n)+b(km+np)+kn$ 

Đồng nhất hệ số:

\(\left\{\begin{matrix} 2m+p=5\\ mp=-3\\ k+2n=0\\ km+np=-7\\ kn=-2\end{matrix}\right.\)

Giải hpt này ta thu được $m=3; n=1; p=-1; k=-2$

Vậy $2a^2+5ab-3b^2-7b-2=(a+3b+1)(2a-b-2)$

b. Đa thức không phân tích được thành nhân tử

lm theo pp đồng nhất hệ số ạ

b: Ta có: \(2x^2-7xy+3y^2+x-3y\)

\(=2x^2-6xy-xy+3y^2+x-3y\)

\(=2x\left(x-3y\right)-y\left(x-3y\right)+\left(x-3y\right)\)

\(=\left(x-3y\right)\left(2x-y+1\right)\)

\(5a^2-14ab-3b^2\\ =5a^2-15ab-ab-3b^2\\ =5a\left(a-3b\right)-b\left(a-3b\right)\\ =\left(5a-b\right)\left(a-3b\right)\)

\(5a^2-14ab-3b^2\)

\(=5a^2-15ab+ab-3b^2\)

\(=5a\left(a-3b\right)+b\left(a-3b\right)\)

\(=\left(a-3b\right)\left(5a+b\right)\)

\(2a^2+8b^2-8ab\)

\(=2\left(a^2-4ab+4b^2\right)\)

\(=2\left(a-2b\right)^2\)

cám ơn nhaaaaa!!!!

2a2+8b2−8ab

=2(�2−4��+4�2)=2(a2−4ab+4b2)

=2(�−2�)2=2(a−2b)2

\(8a^4-2a^2-4a+2\)

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

\(=2\cdot\left(2a-1\right)\cdot\left(2a^3+a^2-1\right)\)

\(8a^4-2a^2-4a+2\)

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

\(=2\left(4a^4-2a^3+2a^3-a^2-2a+1\right)\)

\(=2\left(2a-1\right)\left(2a^3+a^2-1\right)\)

10 000 000 099 = 7 x 1428571443

a) \(=\left(a+2c\right)^2-16=\left(a+2c-4\right)\left(a+2c+4\right)\)

b) \(=3y\left(4-x^2\right)+9\left(4-x^2\right)=3\left(4-x^2\right)\left(y+3\right)\)

\(=3\left(2-x\right)\left(2+x\right)\left(y+3\right)\)

a, a² + 4ac + 4c² - 16 = (a + 2c)² - 4² = (a + 2c -4).(a + 2c +4)

b, 12y - 9x² + 36 - 3x²y = (12y + 36) - (3x²y + 9x²) = 12.(y+ 3) - 3x².(y + 3) =(y + 3).(12 - 3x²)