Question

Solve each equation.log_7 (x^2 + 11) = log_7 15 1) ±42) ±23) ±3.874) ±12

Answer 1

Recall that:

`\log _ab=\log _ac\Leftrightarrow b=c.`

Therefore:

`x^2+11=15.`

Subtracting 11 from the above equation we get:

`\begin{gathered} x^2+11-11=15-11, \\ x^2=4. \end{gathered}`

Therefore:

`x=\pm2.`

Answer: Second option.