Question

Tìm x biết :

3^x+3^x+2 =90

Answer 1

\(3^x+3^x+2=90\)

\(\Leftrightarrow3^x\left(1+1\right)+2=90\)

\(\Leftrightarrow3^x.2+2=90\)

\(\Leftrightarrow3^x.2=92\)

\(\Leftrightarrow3^x=46\)

Answer 2

đề sai ak

Answer 3

      \(3^x+3^x+2=90\)

\(\Leftrightarrow\)\(2.3^x=90-2=88\)

\(\Leftrightarrow\)\(3^x=88:2=44\)

Answer 4

sai đề

Answer 5

Bài làm :

    \(3^x+3^x+2=90\)

           \(2.3^x+2=90\)

                    \(2.3^x=90-2\)

                    \(2.3^x=88\)

                        \(3^x=\frac{88}{2}\)

                        \(3^x=44\)

\(\Rightarrow3.3.3.........3\left(x\text{số}3\right)=40\)