I found the answer to 5, but I couldn't see the rest of worksheet to solve 6 thoroughly.
Both of these problems can be solved through substitution using the variables that you know equal a number.
For example #5: 5(3)(3)-7(3)+4
45-21= 24, and 24+8=28
That is how you solve number 5 and can also solve 6 the same way using the same method.
