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

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Answer 1 · 2016-11-04T03:44:55

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

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

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

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

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

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

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

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