6h is the same thing as saying 6 times h. If we plug 6 in for h, we get 6x6=36. 6x6 does equal 36, so h = 6 is a solution to the problem.
If you plug in 60 for y, you get 60-45=15. 60-45 actually does equal 15, so both sides are equal and y=60 is a solution to the problem
If you plug in x=1/4, you get 1/4 + 1/2 = 3/4. 1/2 = 2/4, and 2/4 + 1/4 = 3/4 so x=1/4 is a solution to the problem
If you plug in w=2 for #5, you get 6x2=120. 6x2 equals 12, not 120, so w=2 is not a solution to the problem
If you plug in n=30 into #6, you get 30/3=12. 30/3 = 10, not 12, so n=30 is not a solution.
Hope this helps!