Solve or simplify: 4 x (12 x 6 – 42x ) + 9

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

If f(x)=x^2- 4 and g(x)=x^2 plus 2 x, (c) (f-/3) = ? (simplify your answer.)

Robert is replacing sod in two square shaped areas of his backyard.one side of the first area is 7.5 feet.one side of the other is 5.7 feet.the sod costs y dollars per square foot.