Question

write the coefficient of y in the expansion of (5-y)^3 i.e.,(5-y)cube

Answer 1

#AlexaRousey here!!

= (5-y)^3

= (5)^3 - y^3 - 3(5)(y)(5-y)

= 125 - y^3 - 15y(5-y)

= 125 - y^3 - 75y + 15y^2

Here coefficient of y is - 75.

Thanks!!

Answer 2

given :- (5 - y)³

we have to find the coefficient of y In the expansion of (5 - y)³

we know that (a - b)³ = a³ - b³ - 3a²b - 3ab²

here a = 5 and b = y

therefore (5 - y)³ = (5)³ - (y)³ - 3(5)²(y) - 3(5)(y)²

= 125 - y³ - 75y - 15y²

hence, the coefficient of y is -75

HOPE THIS HELPS..!!