Question

Tính :

A) 2x.(x+1)

B) (5x - 6)(x - 2)

C) (10x^4y^2 - 5x^3y^2 + 15xy^4) : 5xy

Phân tích đa thức thành nhân tử :

D) 2x(x+y) - 3(x+y)

E) 4x^2 - 49

Tìm x :

x(x+2) - 2x-4 = 0

Answer 1

1, a, \(2x\left(x+1\right)=2x^2+2x\)

b, \(\left(5x-6\right)\left(x-2\right)=5x^2-16x+12\)

c, \(\left(10x^4y^2-5x^3y^2+15xy^2\right):5xy=2x^3y-x^2y+3y\)

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

b, \(4x^2-49=\left(2x\right)^2-7^2=\left(2x+7\right)\left(2x-7\right)\)

3, \(x\left(x+2\right)-2x-4=0\)

\(\Leftrightarrow x\left(x+2\right)-2\left(x+2\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=2\end{matrix}\right.\)