Question

How do you solve `log (-2a+9)=log(7-4a)`?

Answer 1

Set the expressions equal to find `a=-1`

Explanation:

`log(-2a+9)=log(7-4a)`

If the log of an expression equals the log of another expression, the two expressions must be equal.

`-2a+9=7-4a`
`+4acolor(white)(aaaaa^22a)+4a`

`color(white)(a^2)2a+9=color(white)(aa)7`
`color(white)(aa^2a)-9=-9`

`color(white)(a^2)(2a)/2=(-2)/2`

`color(white)(aaa^2)a=-1`