Question

Tìm x biết  x^2 - 5x + 6 =0

Answer 1

x^2-5x+6=0 
<=>x^2-2x-3x+6=0 
<=>(x^2-2x)-(3x-6)=0 
<=>x(x-2)-3(x-2)=0 
<=>(x-2)(x-3)=0 
<=>x-2=0 hoac x-3=0 
<=>x=2 hoac x=3

Answer 2

\(x^2-5x+6=x^2-2x-3x+6=x\left(x-2\right)-3\left(x-2\right)=\left(x-3\right)\left(x-2\right)=0\)

=> x-3=0 hoặc x-2=0

=> x=3 hoặc x=2