Question

i need help on adding mixed fractions with unlike denominators

Answer 1

It’s about 15.5111, It’s ok if you don’t get it, just simplify it to get a improper fraction and change the denominator to a similar number as the other.

Answer 2

we'll first convert the mixed fractions to "improper", and proceed from there,

$\bf \stackrel{mixed}{7\frac{1}{9}}\implies \cfrac{7\cdot 9+1}{9}\implies \stackrel{improper}{\cfrac{64}{9}} \\\\\\ \stackrel{mixed}{8\frac{2}{5}}\implies \cfrac{8\cdot 5+2}{5}\implies \stackrel{improper}{\cfrac{42}{5}}\\\\ -------------------------------\\\\ 7\frac{1}{9}+8\frac{2}{5}\implies \cfrac{64}{9}+\cfrac{42}{5}\impliedby \textit{our LCD will be }45\implies \cfrac{(5)64~+~(9)42}{45} \\\\\\ \cfrac{320+378}{45}\implies \cfrac{698}{45}\implies 15\frac{23}{45}$