Question

Tìm x (X+1)(x+3)-(x+2)(x+5)=2

Answer 1

\(\Rightarrow x^2+4x+3-x^2-7x-10=2\\ \Rightarrow-3x=9\Rightarrow x=-3\)

Answer 2

⇒x (x²+4x+3)−x²−7x−10=2

⇒ x³ +4x² +3x -x² -7x=12

<=> x³ +3x² -4x-12=0

<=> x³ -2x² +5x² -10x+6x -12 =0

<=> x² (x-2) +5x(x-2) +6(x-2) =0

<=> (x² +5x+6)(x-2) =0

<=> (x² +3x +2x +6)(x-2)=0

<=>( x.(x+3) +2.(x+3) )(x-2)=0

<=>(x+2)(x+3)(x-2)=0

<=> x=-2 hoặc x= -3 hoặc x=2