Question

9b-1/b^2-9 - 6b-10/b^2-9 при b=4,5

Answer 1

$\frac{9b-1}{b^{2}-9}-\frac{6b-10}{b^{2}-9} =\frac{9b-1-6b+10}{b^{2}-9} =\frac{3b+9}{b^{2}-9} =\frac{3(b+3)}{(b-3)(b+3)} =\frac{3}{b-3}$

$\frac{3}{4.5-3}=\frac{3}{1.5}=2$