Hi there, can someone please help me with my math homework. It’s only the blue highlighted sums I need. Please help I’ll really appreciate it.

When a formula is solved for a particular variable, several different equivalent forms may be possible. if we solved a=1/2bh for h, one possible correct answer is h=2a/b . which one of the following is not equivalent to this? a. h= 2(a/b) b. h= 2a(1/b) c. h= a/1/2b d. h= 1/2a/b

What is sin 7x/4 ? i need on this urgent trig

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?