How many solutions does this system of equations have?

x/4+y/9=27
3x/2+2y/3=19

Solve - pv + 40 < 65 for v solve 7w - 3r = 15 for r

Mindy bought 5/8 pound of almonds and a 3/4 pound of walnuts. which pair of fraction cannot be used to find how many pounds of nuts she bought in all.

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative