Answer:
Let s stand for soup, and f stand for frozen dinners.
s + f = 14
s(300mg) + f(500mg) = 5200mg
Explanation:
He bought 14 frozen dinners and soups all together, so whatever number you plug in for soups and frozen dinners has to equal 14. Then, you have to make the equations also equal 5200mg. So whatever you plug in for the first equation needs to also work for the second.