Question

tìm x thuộc Z

a)78-5 lx-1l= -35+43

b) (3lxl-2⁴).7³=2.7⁴

Answer 1

a/ \(78-5.|x-1|=-35+43.\)

\(78-5.|x-1|=8\)

\(5.|x-1|=78-8\)

\(5.|x-1|=70\)

\(|x-1|=70:5\)

\(|x-1|=14\)

\(\orbr{\begin{cases}x-1=14\\x-1=-14\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=15\\x=-13\end{cases}}\)Vậy :.....

b/ \(\left(3.|x|-2^4\right).7^3=2.7^4\)

\(\left(3.|x|-2^4\right)=2.7^4:7^3\)

\(3.|x|-2^4=2.7=14\)

\(3.|x|=14+2^4=14+16=30\)

\(|x|=30:3=10\)

\(\orbr{\begin{cases}x=10\\x=-10\end{cases}}\)Vậy : .....

Nhớ k cho mình nhé! Thank you!!!