6(x+1)^2+2(x-1)(x^2+x+1)-2(x+1)^3=32 tìm x Question 6(x+1)^2+2(x-1)(x^2+x+1)-2(x+1)^3=32 tìm x in progress 0 Môn Toán Kiệt Gia 4 years 2020-11-01T15:42:31+00:00 2020-11-01T15:42:31+00:00 2 Answers 142 views 0
Answers ( )
Đây ạ

Đáp án:
$x=5$
Giải thích các bước giải:
$6.(x+1)^2+2.(x-1).(x^2+x+1)-2.(x+1)^3=32$
$⇔6.(x^2+2x+1)+2.(x^3-1)-2.(x^3+3x^2+3x+1)=32$
$⇔6x^2+12x+6+2x^3-2-2x^3-6x^2-6x-2=32$
$⇔6x+2=32$
$⇔6x=30$
$⇔x=5$