How does (15e^-1/2)(-15e^-1/2) -(5e^-1/2)^2 =40e^-1
I got -225e^-1 -25e^-1 =-250e^-1not 40e^-1
show steps if you know
(15e^-1/2)(-15e^-1/2) = -225e^-1
(5e^-1/2)^2 = 25e^-1
So, I agree with your result. Maybe a typo on the answer key.
Unless maybe it was
(√15e^-1/2)(-√15e^-1/2) = -15e^-1
That would have given -40e^-1. Still not what you want, but hey ...
I tried (15e)^-1/2, but that would have wound up with 1/15 e^-1...