(x+1)^3+3x(x+2)+x^2(x-1)+5x^2(x-1)=15 help me!!!!! Cần gấp vote 5* Question (x+1)^3+3x(x+2)+x^2(x-1)+5x^2(x-1)=15 help me!!!!! Cần gấp vote 5* in progress 0 Môn Toán Nick 4 years 2020-12-01T06:15:53+00:00 2020-12-01T06:15:53+00:00 2 Answers 84 views 0
Answers ( )
`(x+1)^3+3x(x+2)+x^2(x-1)+5x^2(x-1)=15`
`<=>x^3+3x^2+3x+1+3x^2+6x+x^3-x^2+5x^3-5x^2-15=0`
`<=>(x^3+x^3+5x^3)+(3x^2+3x^2-x^2-5x^2)+(3x+6x)+(1-15)=0`
`<=>7x^3+9x-14=0`
`<=>` Nghiệm sấu lắm bạn.
Giải thích các bước giải:
`(x+1)^3+3x(x+2)+x^2(x-1)+5x^2(x-1)=15`
`<=>x^3+3x^2+3x+1+3x^2+6x+x^3-x^2+5x^3-5x^2=15`
`<=>x^3+3x^2+3x+1+3x^2+6x+x^3-x^2+5x^3-5x^2-15=0`
`<=>7x^3+9x-14=0`
`<=>….?`