Answer:
x - 6
Step-by-step explanation:
divide number of mangoes bought by number of groups, that is
[tex]\frac{x^2-9}{x+3}[/tex]
= [tex]\frac{(x+3)(x-3)}{x+3}[/tex] ← numerator is difference of squares
cancel the factor (x + 3) on numerator/denominator
number in each group = x - 3
subtract 3 rotten mangos from group for good mangoes
good mangoes = x - 3 - 3 = x - 6