Question

Tìm x thuộc Z:

k) |x - 1| - x = x - 5

p) |x + 4| + x = 12 - x

i) (x - 3) . (x - 3)³ = 81

z) 2^{3x - 2} : 2^{x - 3} = 128²

Answer 1

i,(x-3).(x-3)³=81 =>(x-3)⁴=81 =>(x-3)⁴=3⁴ =>x-3=3 =>x=3+3 =>x=6

Answer 2

k: |x-1|-x=x-5

=>|x-1|=2x-5

\(\Leftrightarrow\left\{{}\begin{matrix}x>=\dfrac{5}{2}\\\left(2x-5-x+1\right)\left(2x-5+x-1\right)=0\end{matrix}\right.\Leftrightarrow x\in\varnothing\)

p: |x+4|+x=12-x

=>|x+4|=12-2x

\(\Leftrightarrow\left\{{}\begin{matrix}x< =6\\\left(-2x+12+x+4\right)\left(-2x+12-x-4\right)=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x< =6\\\left(-x+16\right)\left(-3x+8\right)=0\end{matrix}\right.\Leftrightarrow x=16\)

z: \(\Leftrightarrow2^{3x-2-x+3}=2^{14}\)

=>2x+1=14

hay x=13/2