À mình nhầm 5x^x2x2 chuyển thành 5x²

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2x^3-5x^2+6x-15

=(2x^3+6x)-(5x^2+15)

=2x(x^2+3)-5(x^2+3)

=(x^2+3)(2x-5)

a: \(4x^2-x-5=\left(4x-5\right)\left(x+1\right)\)

b: \(x^2-2x-15=\left(x-5\right)\left(x+3\right)\)

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

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

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

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

= ( x² - 4y² ) - ( 2x + 4y )

= ( x - 2y ) ( x + 2y ) - 2 ( x - 2y )

= ( x - 2y ) ( x + 2y - 2 )

x2 + 2x – 3

= x2 + 2x + 1 – 4

= (x + 1)2 – 22

= (x + 1 + 2)(x + 1 – 2)

= (x + 3)(x – 1)

\(x^2+2x+1-16=\left(x+1\right)^2-4^2=\left(x+1-4\right).\left(x+1+4\right)=\left(x-3\right).\left(x+5\right)\)

\(x^2+2x+1-16=\left(x^2+2x+1\right)-4^2=\left(x+1\right)^2-4^2=\left(x+1-4\right)\left(x+1+4\right)=\left(x-3\right)\left(x+5\right)\)

\(x^2+2x+1-16=\left(x+5\right)\left(x-3\right)\)

\(x^2-y^2+2x+1\\=(x^2+2x+1)-y^2\\=(x+1)^2-y^2\\=(x+1-y)(x+1+y)\)

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

Cách 1:  x 2  + 2xy - 15 y 2 = ( x 2  + 2xy + y 2 ) - 16 y 2

= x + y 2 - 4 y 2

= (x + y + 4y)(x + y – 4y)

= (x + 5y)(x – 3y).

Cách 2:  x 2  + 2xy - 15 y 2  =  x 2  + 5xy – 3xy - 15 y 2

= x(x + 5y) – 3y(x + 5y)

= (x – 3y)(x + 5y).