a: \(=4x^2-25-4x^2+12x-9-12x=-34\)

b: \(=8y^3-12y^2+6y-1-2y\left(4y^2-12y+9\right)-12y^2+12y\)

\(=8y^3-24y^2+18y-1-8y^3+24y^2-18y=-1\)

c: \(=x^3+27-x^3-20=7\)

d: \(=3y\left(9y^2+12y+4\right)-27y^3+1-36y^2-12y-1\)

\(=27y^3+36y^2+12y-27y^3-36y^2-12y\)

=0

bài này đặt ẩn đi nhìn hệ to quá cx ngại

Bài 2 :

a) \(\left(5x^2y-8xy^2+y^3\right)\left(2x^3+x^2y-3y^2\right)\)

\(=10x^5y+5x^4y^2-15x^2y^3-16x^4y^2-8x^3y^3+24xy^4+2x^3y^3+x^2y^4-3y^5\)

\(=10x^5y-11x^4y^2-6x^3y^3+x^2y^4-15x^2y^3+24xy^4-3y^5\)

a. 12xy² - 8x²y = 4xy . (3y - 2x)

b. 3x + 3y - x² - xy = (3x + 3y) - (x² + xy) = 3 . (x + y) - x . (x + y) = (x + y)(3 - x)

GIUSP MIK VS MN ƠI

Bài 2:

a: =>2x^2-8+3x-2x^2=15

=>3x=23

=>x=23/3

b: \(\Leftrightarrow\left(x+3\right)\left(x-5\right)=0\)

=>x=5 hoặc x=-3

c: =>x^2+7x-30=0

=>(x+10)(x-3)=0

=>x=3 hoặc x=-10

help me!!

đây là 1 câu hay 2 câu vậy ạ ?

nếu là 2 câu thì ra câu trên là : -2x + 4y + 8

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

=(2x-y)(x-y)-(2x-y)(2y-3x)-(4x-3y)²

=(2x-3y)(x-y-2y+3x)-(4x-3y)²

=(2x-3y)(4x-3y)-(4x-3y)²

^{=(4x-3y)(2x-3y-4x+3y)}

=(4x-3y))(-2x)

\(a,3x^3y^3-15x^2y^2=3x^2y^2\left(xy-5\right)\)

\(b,5x^3y^2-25x^2y^3+40xy^4\)

\(=5xy^2\left(x^2-5xy+8y^2\right)\)

\(c,-4x^3y^2+6x^2y^2-8x^4y^3\)

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

\(d,a^3x^2y-\frac{5}{2}a^3x^4+\frac{2}{3}a^4x^2y\)

\(=a^3x^2\left(y-\frac{5}{2}x^2+\frac{2}{3}ay\right)\)

\(e,a\left(x+1\right)-b\left(x+1\right)=\left(x+1\right)\left(a-b\right)\)

\(f,2x\left(x-5y\right)+8y\left(5y-x\right)\)

\(=2x\left(x-5y\right)-8y\left(x-5y\right)=\left(x-5y\right)\left(2x-8y\right)\)

\(g,a\left(x^2+1\right)+b\left(-1-x^2\right)-c\left(x^2+1\right)\)

\(=\left(x^2+1\right)\left(a-b-c\right)\)

\(h,9\left(x-y\right)^2-27\left(y-x\right)^3\)

\(=9\left(x-y\right)^2+27\left(x-y\right)^3\)

\(=9\left(x-y\right)^2\left(1+3x-3y\right)\)

$a,3x^3{y}^3-15x^2{y}^2=3x^2{y}^2\left(xy-5\right)$

$b,5x^3{y}^2-25x^2{y}^3+40x{y}^4$

$=5x{y}^2\left(x^2-5xy+8y^2\right)$

$c,-4x^3{y}^2+6x^2{y}^2-8x^4{y}^3$

$=-2x^2{y}^2\left(2x-3+4x^{2}y\right)$

$d,a^3{x}^{2}y-\frac{5}{2}{a}^3{x}^4+\frac{2}{3}{a}^4{x}^{2}y$

$=a^3{x}^2\left(y-\frac{5}{2}{x}^2+\frac{2}{3}ay\right)$

$e,a\left(x+1\right)-b\left(x+1\right)=\left(x+1\right)\left(a-b\right)$

$f,2x\left(x-5y\right)+8y\left(5y-x\right)$

$=2x\left(x-5y\right)-8y\left(x-5y\right)=\left(x-5y\right)\left(2x-8y\right)$

$g,a\left(x^2+1\right)+b\left(-1-x^2\right)-c\left(x^2+1\right)$

$=\left(x^2+1\right)\left(a-b-c\right)$

$h,9{\left(x-y\right)}^2-27{\left(y-x\right)}^3$

$=9{\left(x-y\right)}^2+27{\left(x-y\right)}^3$