Question

21y=196-y2 please answer​

Answer 1

step by step explannation :

21y = 196 - y^2

or y^2 + 21y - 196 =0

or y^2 + (28 - 7)y - 196 =0

or y^2 + 28y -7y -196 =0

or y(y + 28 ) - 7( y + 28 ) =0

or (y-7)(y+28) =0

either y-7 = 0 , y = 7

or y + 28 = 0 , y = -28