What is the greatest common factor of 12, 40 and 68

What is 32+4 x (16 x 1/2) -2 show your work}

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

If y varies directly as x2 and y=6 when x=6, find the constant of variation.