the cost of three pencil and one eraser is #22, while the cost of four pencils and three eraser is #42, find the numbers

Answer 1

3p + e = 22
4p + 3e = 42

I would use substitution, from the first
e = 22-3p
plug into the 2nd

4p + 3(22-3p) = 42
4p + 66 - 9p = 42
-5p = -24
p = 4.80 , then e = 7.60