Question

[Rita Yoo]

Giải các pt sau:

a, (4x-1)(x+5)=(2x-3)^{^2}

b, x(x+1)(x+2)(x+3)=24

c, x^{^2}-2x+1=3x(x-1)

d,\(\frac{x+1}{2017}+\frac{x+2}{2015}=\frac{x+2014}{3}+\frac{x+2013}{4}\)

Answer 1

[Không Tên]

b)       \(x\left(x+1\right)\left(x+2\right)\left(x+3\right)=24\)

\(\Leftrightarrow\)\(\left(x^2+3x\right)\left(x^2+3x+2\right)-24=0\)

Đặt   \(x^2+3x=t\)   ta có:

          \(t\left(t+2\right)-24=0\)

\(\Leftrightarrow\)\(t^2+2t-24=0\)

\(\Leftrightarrow\)\(\left(1-4\right)\left(1+6\right)=0\)

đến đây bn giải tiếp