Question

Tìm x

a.  2x^3+3x^2-2x-3=0

b.  3x(x-1)+7x^2(x-1)=0

c.  x(x+4)×(x+6)×(x+10)+128=0

Answer 1

b,   <=> (x-1)(3x+7x^2)=0

<=> x(x-1)(7x+3)=0

<=> x=0;x=1;x=-3/7

Answer 2

a,  2x^3+3x^2-2x-3=0

<=> 2x^3-2x^2+5x^2-5x+3x-3=0

<=> 2x^2(x-1)+5x(x-1)+3(x-1)=0

<=> (x-1)(2x^2+5x+3)=0

<=> (x-1)(2x^2+2x+3x+3)=0

<=> (x-1)[2x(x+1)+3(x+1)]=0

<=> (x-1)(x+1)(2x+3)=0

<=>x=1;x=-1;x=-3/2

<=>