Use main properties of powers
(a^m)^n=a^{m\cdot n};(am)n=am⋅n;
\dfrac{1}{a^n}=a^{-n}an1=a−n
to simplify given equation.
1.
4^x=(2^2)^x=2^{2x}.4x=(22)x=22x.
2.
\left(\dfrac{1}{8}\right)^{x+5}=\left(\dfrac{1}{2^3}\right)^{x+5}=(2^{-3})^{x+5}=2^{-3x-15}.(81)x+5=(231)x+5=(2−3)x+5=2−3x−15.
3. Then the equation is
2^{2x}=2^{-3x-15}.22x=2−3x−15.
The bases are the same, so equate the powers:
2x=-3x-15,
2x+3x=-15,
5x=-15,
x=-3.
Answer: for x=-3.
