Can u guys answer these last 4 questions for me w/ work shown and also label the ones u guys did so I won’t get them mixed up

1.)yx divided by 2 use x=7 and y=2

2.)m-n divided by 4 use m=5 and n=8

3.)x-y+6 Use x=6 and y=1

4.)z+x^3 use x=1 and z=19