Question

[Trần Minh Sơn]

Nhờ

Nh

x

Nhờ giải giúp bài tập

Answer 1

[hoshimiya ichigo]

chiu ba bao tui lam lo lon ak

Answer 2

[Nguyễn Huy Tú]

Bài 3B : 

a, \(\left(x+4\right)^2-\left(2x+1\right)^2=3\left(x-3\right)\)

\(\Leftrightarrow\left(x+4-2x-1\right)\left(x+4+2x+1\right)=3\left(x-3\right)\)

\(\Leftrightarrow-\left(x-3\right)\left(3x+5\right)=3\left(x-3\right)\Leftrightarrow\left(x-3\right)\left(-5-3x\right)-3\left(x-3\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(-8-3x\right)=0\Leftrightarrow x=-\frac{8}{3};x=3\)

b, \(x^3-8=2x^2-4x\Leftrightarrow\left(x-2\right)\left(x^2+2x+4\right)-2x\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(x^2+4>0\right)=0\Leftrightarrow x=2\)

c, \(x^3-6x^2+8x=0\Leftrightarrow x\left(x^2-6x+8\right)=0\)

\(\Leftrightarrow x\left(x^2-6x+9-1\right)=0\Leftrightarrow x\left[\left(x-3\right)^2-1\right]=0\)

\(\Leftrightarrow x\left(x-4\right)\left(x-2\right)=0\Leftrightarrow x=0;x=2;x=4\)