Question

сократите дробь a^2+6a+9/a^2-9​

Answer 1

$\bf\displaystyle~\frac{\bf\overbrace{a^2+6a+9}^{(a+3)^2} {}}{\underbrace{a^2-9} _{(a-3)(a+3)} }=\frac{(a+3)^2}{(a-3)(a+3)} =\frac{a+3}{a-3} .\\\\\tt~\star~a^2+2ab+b^2=(a+b)^2~;~\star~a^2-b^2=(a-b)(a+b)~\star.$