No, it does not equal 0. Lets multiply it out and see what it actually equals.
15/25 * 25/15
15*25 / 25*15
375 / 375
Anything over itself is 1, so the final answer for the multiplication is 1.
ACB + BAC =90
ACB + 37 = 90
ACB = 53
Tan (53) = 10/x
X= 7.536
(Hope this helped have a great day)
-1 - 10n is a simple version
Im not to sure but I am pretty sure it's 1/10