Question

Phân tích thành nhân tử                                                x^2-y^2+7x-7y                                                            x^2-10x+25-9y^2

Answer 1

\(x^2-y^2+7x-7y=\left(x^2-y^2\right)+\left(7x-7y\right)=\left(x-y\right)\left(x+y\right)+7\left(x-y\right)=\left(x-y\right)\left(x+y+7\right)\)

\(x^2-10x+25-9y^2=\left(x^2-10x+25\right)-\left(3y\right)^2=\left(x-5\right)^2-\left(3y\right)^2=\left(x-3y-5\right)\left(x+3y-5\right)\)

Answer 2

\(x^2-y^2+7x-7y=\left(x-y\right)\left(x+y\right)+7\left(x-y\right)=\left(x-y\right)\left(x+y+7\right)\)

\(x^2-10x+25-9y^2=\left(x-5\right)^2-\left(3y\right)^2=\left(x-5-3y\right)\left(x-5+3y\right)\)

Answer 3

1. x² - 10x + 25 - 9y²

<=> x² - 10x + 5² - (3y)²

<=> (x - 5)² - (3y)²

<=> (x - 5 - 3y)(x - 5 + 3y)

2. x² - y² + 7x - 7y

<=> (x - y)(x + y) + 7(x - y)

<=> (x + y + 7)(x - y)

Answer 4

a: \(x^2-y^2+7x-7y\)

\(=\left(x-y\right)\left(x+y\right)+7\left(x-y\right)\)

\(=\left(x-y\right)\left(x+y+7\right)\)

b: \(x^2-10x+25-9y^2\)

\(=\left(x-5\right)^2-9y^2\)

\(=\left(x-5-3y\right)\left(x-5+3y\right)\)