Question

I have a little bit confusion

please help me

Answer 1

You can solve this sum using the identity (x+a)(x+b)=x² + x(a+b) + ab

$(\frac{1}{y} + 4)(\frac{1}{y}+ (-9)) =\frac{1}{y^2} + \frac{1}{y} (4-9) + (4×-9) =\frac{1}{y^2} - \frac{5}{y} - 36$

Hope this helps :)