Question

[Tranphuonganh]

Phân tích các đa thức sau thành phân tử 

a,2x(x-5)+3(x-5)   

b,(x^2-9)+(x-3)(3-2x)   

c,x^2-2xy+y^2     

d. x^2-x-(4x-4)

e, (2x-5)^2-(x+2)^2 

   f. x^2+7x-8

Answer 1

[Bùi Anh Tuấn]

\(a,2x\left(x-5\right)+3\left(x-5\right)\)

\(\Rightarrow\left(x-5\right)\left(2x+3\right)\)

\(b,\left(x^2-9\right)+\left(x+3\right)\left(3-2x\right)\)

\(\Rightarrow\left(x+3\right)\left(x-3\right)+\left(x+3\right)\left(3-2x\right)\)

\(\Rightarrow\left(x+3\right)\left(x-3+3-2x\right)\)

\(\Rightarrow\left(x+3\right)\left(-x\right)\)

\(c,x^2-2xy+y^2\)

\(\Rightarrow\left(x-y\right)^2\)

\(d,x^2-x-\left(4x-4\right)\)

\(\Rightarrow x^2-x-4x+4\)

\(\Rightarrow x\left(x-1\right)-4\left(x-1\right)\)

\(\Rightarrow\left(x-1\right)\left(x-4\right)\)

\(e,\left(2x-5\right)^2-\left(x+2\right)^2\)

\(\Rightarrow\left(2x-5-x-2\right)\left(2x-5+x+2\right)\)

\(\Rightarrow\left(x-7\right)\left(3x-3\right)\)

\(f,x^2+7x-8\)

\(\Rightarrow x^2-x+8x-8\)

\(\Rightarrow x\left(x-1\right)+8\left(x-1\right)\)

\(\Rightarrow\left(x-1\right)\left(x+8\right)\)