Question

Приведите подобные слагаемые: -2/3у+5/21у+1/7у
Срочно!!!!!

Answer 1

$\displaystyle -\frac23y+\frac5{21}y+\frac17y=-\frac23y+\frac5{21}y+\frac3{21}y=-\frac{14}{21}y+\frac8{21}y=-\Big(\frac{14}{21}-\frac8{21}\Big)y=\\\\=-\frac6{21}y\\\\-\frac6{21}y=-\frac2{7}y$