Question

If 81 y^2-k= [9y+1/2] [9y-1/2]​

Answer 1

Step-by-step explanation:

81 y²-k= [9y+1/2] [9y-1/2]

81y²-k= (9y)²-(1/2)². {using (a+b)(a-b)=a²-b²}

81y²-k=81y²-1/4

-2k= -1/4

2k=1/4

k=1/8