Question

7^x + 3. 7^x+1 =1078

Answer 1

\(\Leftrightarrow7^x\left(1+3\cdot7\right)=1078\)

=>7^x=49

=>x=2

Answer 2

\(7^x+3.7^{x+1}=1078\)

\(7^x.\left(1+3.7\right)=1078\)

\(7^x=\dfrac{1078}{22}\)

\(7^x=49\)

\(7^x=7^2\)

\(x=2\)

Vậy \(x=2\)