Question

[Lâm Ngọc]

a, x3x3 (x+4)+4x+√x2+2x+2020x2+2x+2020 =2(1009-3x2x2 )

b, 4x2x2 +14x+1=4√6x+106x+10

c, 3x2x2 +6x-3= √(x+7)/3

d, x3x3 -x2x2 -x-5=(x+4)√x+2

Answer 1

[alibaba nguyễn]

d/ \(x^3-x^2-x-5=\left(x+4\right)\sqrt{x+2}\)

\(\Leftrightarrow\left(x-1\right)^3+2\left(x-1\right)^2+2\left(x-1\right)=\left(x+2+2\right)\sqrt{x+2}+2\left(x+2\right)\)

Đặt \(\hept{\begin{cases}x-1=a\\\sqrt{x+2}=b\end{cases}}\)

\(\Rightarrow a^3+2a^2+2a=b^3+2b^2+2b\)

\(\Leftrightarrow a=b\)

Làm nốt