Question

1.phan tich cac da thưc sau thành nhan tử

a. xy + xz -2y -2z

b. x²- 6xy + 9y² - 25z²

c. x² -2x + 2y -xy

d. (x² + 1)² - 4x²

e. x² -y² +2yz - z²

^{mong mọi người jup dỡ cảm ơn nhiều ạ.}

Answer 1

a) xy+xz-2y-2z=x(y+z)-2(y+z)=(y+z)(x-2)

b) \(x^2-6xy+9y^2-25z^2=\left(x-3y\right)^2-\left(5z\right)^2=\left(x-3y-5z\right)\left(x-3y+5z\right)\)

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

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

e)\(x^2-y^2+2yz-z^2=x^2-\left(y^2-2yz+z^2\right)=x^2-\left(y-z\right)^2=\left(x+y-z\right)\left(x-y+z\right)\)