a)$\frac{-4}{9}$ . $\frac{7}{15}$ +$\frac{4}{-9}$ .$\frac{8}{15}$
=$\frac{-4}{9}$ . $\frac{7}{15}$ +$\frac{-4}{9}$ .$\frac{8}{15}$
=$\frac{-4}{9}$($\frac{7}{15}$+$\frac{8}{15}$ )
=$\frac{-4}{9}$.1
=$\frac{-4}{9}$
b)2$\frac{13}{27}$ -$\frac{7}{15}$ +3$\frac{14}{27}$ -$\frac{8}{15}$
=2$\frac{13}{27}$ +3$\frac{14}{27}$ -($\frac{8}{15}$ +$\frac{7}{15}$)
=(2$\frac{13}{27}$ +3$\frac{14}{27}$) -1
=($\frac{26}{27}$ +$\frac{42}{27}$)-1
=$\frac{68}{27}$ -1
=$\frac{68}{27}$-$\frac{27}{27}$
=$\frac{41}{27}$
c)11$\frac{1}{4}$ -(2$\frac{5}{7}$ +5$\frac{1}{4}$ )
=11$\frac{1}{4}$ -2$\frac{5}{7}$ -5$\frac{1}{4}$
=(11$\frac{1}{4}$-5$\frac{1}{4}$) -2$\frac{5}{7}$
=$\frac{1}{4}$(11-5)-2$\frac{5}{7}$
=6$\frac{1}{4}$-2$\frac{5}{7}$
=$\frac{3}{2}$ -$\frac{10}{7}$
=$\frac{21}{14}$-$\frac{20}{14}$
=$\frac{1}{14}$
d)-/-7/.[$(-2)^{4}$+(-36):(-3)²]-(-5)³
=-7.[$(2)^{4}$+(-36):(3)²]-(-5)³
=-7.[$(2)^{4}$+(-4)].(5)³
=-7.[16+(-4)]+125
=-7.12+125
=-84+125
=41
