Question

a) \(4^x\)=64

b) 35⋮ x

c) 135- ( x-5)= 105:3

d) x ⋮ 25 và x <100

Answer 1

a) \(4^{x^{ }}=64\)

\(\Rightarrow4^x=4^3\)

\(\Rightarrow x=3.\)

b) Vì \(35⋮x\)

\(\Rightarrow x\inƯ\left(35\right)=\left\{1;5;7;35\right\}\)

Vậy \(x\in\left\{1;5;7;35\right\}\)

c) \(135-\left(x-5\right)=105:3\)

\(\Leftrightarrow\)\(135-\left(x-5\right)=35\)

\(\Leftrightarrow x-5=135-35\)

\(\Leftrightarrow x-5=100\)

\(\Leftrightarrow x=100+5\)

\(\Leftrightarrow\) \(x=105.\)

d) Vì \(x⋮25\)

\(\Rightarrow x\in B\left(25\right)=\left\{0;25;50;75;100;...\right\}\)

Mà \(x< 100\)

\(\Rightarrow x\in\left\{0;25;50;75\right\}\)