--x+y= -5 and y-2x = -12

Keisha makes a large sandwich for a family picnic she takes 1/2 of them the sandwich to the picnic her family eats 3/8 of the whole sandwich what fraction of the whole sandwich does keisha bring back from the picnic

What is the exact volume of the cylinder? 16in going into the middle of the top of the cylinder and 40in in height a) 25,600(pi)3 b)10,240(pi)3 c)1280(pi)3 d)640(pi)3

Find the value of the cosine for angle a