Question

Tìm x:

|x| - 3 = 4

Tính

\(\frac{10^3+2.5^3+5^3}{55}\)

nhanh nha

Answer 1

\(\left|x\right|-3=4\)

\(\Rightarrow\left|x\right|=4+3\)

\(\Rightarrow\left|x\right|=7\)

\(\Rightarrow x\in\left\{-7;7\right\}\)

\(\frac{10^3+2.5^3+5^3}{55}=\frac{2^3.5^3+5^3\left(1+2\right)}{5.11}=\frac{8.5^3+5^3.3}{5.11}=\frac{5^3\left(8+3\right)}{5.11}\)

\(=\frac{5^3.11}{5.11}=\frac{5^3}{5}=5^2=25\)

Answer 2

Bài 1 :

\(\left|x\right|-3=4\)

\(\left|x\right|=7\)

\(\Rightarrow\orbr{\begin{cases}x=7\\x=-7\end{cases}}\)

Vậy...

Bài 2 :

\(\frac{10^3+2\cdot5^3+5^3}{55}\)

\(=\frac{2^3\cdot5^3+2\cdot5^3+5^3}{5\cdot11}\)

\(=\frac{5^3\cdot\left(2^3+2+1\right)}{5\cdot11}\)

\(=\frac{5^3\cdot11}{5\cdot11}\)

\(=5^2\)