Whats 10x10+3942x238 divided by 12

Pls! does anybody know a shortcut for answering these types of questions in the future?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

Non-euclidean geometry was discovered when, in seeking cleaner alternatives to the fifth postulate, it was found that the negation could also be true a. true b.false