a) \(8^x:4^x=4\)
\(\Rightarrow\left(8:4\right)^x=4\)
\(\Rightarrow2^x=4\)
\(\Rightarrow2^x=2^2\)
\(\Rightarrow x=2\)
Vậy \(x=2.\)
b) \(\frac{-4,4}{9,9}=\frac{x}{1,89}\)
\(\Rightarrow x.9,9=\left(-4,4\right).1,89\)
\(\Rightarrow x.9,9=-8,316\)
\(\Rightarrow x=\left(-8,316\right):9,9\)
\(\Rightarrow x=-0,84\)
Vậy \(x=-0,84.\)
Chúc bạn học tốt!
8x:4x=4
(8:4)x=4
2x=4
2x=22
Vậy x=2