Question

tìm x biết :7^x-7^x+2=-2352

Answer 1

\(7^x-7^{x+2}=-2352=7^x-7^x.7^2\Rightarrow7^x-7^x.49=-2352\Rightarrow7^x.-48=-2352\)

\(\Rightarrow7^x=-2352:-48=49=7^2\Rightarrow x=2\)

Answer 2

\(7^x-7^{x+2}=-2352\)

\(7^x\left(1-49\right)=-2352\)

\(7^x.\left(-48\right)=-2352\)

\(\Rightarrow7^x=49\Leftrightarrow x=2\)

Answer 3

\(7^x-7^{x+2}=-2352\)

\(\Rightarrow7^x-7^x.7^2=-2352\)

\(\Rightarrow7^x.\left(1-49\right)=-2352\)

\(\Rightarrow7^x.\left(-48\right)=-2352\)

\(\Rightarrow7^x=49=7^2\)

\(\Rightarrow x=2\)

Vậy \(x=2\)