(7y)^2-y(y+1). при y=-1/15решите пж
(7y)²-y(y+1)
49y²-y²-y
48y²-y
48(-1/15)²-(-1/15)
1)(-1/15)²=-1/15*(-1/15)=1/15*1/15=1/225
2)48*1/225=(48*1)/225=48/225=8/39
3)8/39-(-1/15)=8/39+1/15=40/195+13/195=53/195
Ответ:53/195