r + 2 → B
Factor the numerators/ denominators of both fractions
r² + 7r + 10 = (r + 2)(r + 5)
3r - 30 = 3(r - 10)
r² - 5r - 50 = (r - 10)(r + 5)
the product now becomes
[tex]\frac{(r + 2)(r + 5)}{3}[/tex] × [tex]\frac{3(r - 10)}{(r - 10)(r + 5)}[/tex]
the following factors on the numerators / denominators cancel
3, (r + 5 ) and ( r - 10 ) leaving simplest form
r + 2
