Question

Как решить:
-0,6y*(-0,9)
-8а*2,5b
-5х*(-0,8y)*0,4z
9/28а * 7/18*(-b)
2 5/8х*(-16/63y)

Answer 1

$\displaystyle \tt -0,6y\cdot(-0,9)=0,54y\\\\ \displaystyle \tt -8a\cdot2,5b=-20ab\\\\ \displaystyle \tt -5x\cdot(-0,8y)\cdot0,4z=-1,6xyz\\\\ \displaystyle \tt \frac{9}{28}a\cdot\frac{7}{18}\cdot(-b)=-\frac{1}{4}a\cdot\frac{1}{2}b=-\frac{1}{8}ab=-0,125ab\\\\ \displaystyle \tt 2\frac{5}{8}x\cdot\bigg(-\frac{16}{63}y\bigg)=\frac{21}{8}x\cdot\bigg(-\frac{16}{63}y\bigg)=-x\cdot\frac{2}{3}y=\frac{2}{3}xy$