I need help solving these word problems

4. Jeffrey and Robert are very hungry after working out. For lunch, Jeffrey has two slices of veggie lover's pizza and one slice of plain pizza for a total of 858 calories. Robert has two slices of plain pizza and one slice of veggie lover's pizza for a total of 846 calories. Write and solve a system of linear equations to find the number of calories in one slice of veggie lover's pizza and the number of calories in one slice of plain pizza. a. What are the two quantities you are asked to find? Be specific. Label one of the quantities x, and the other y (or choose your own variables.) b. Focus on the phrase, "...Jeffrey has two slices of veggie lover's pizza and one slice of plain pizza for a total of 858 calories". Think about the meaning of x and y from part (a) and then write an equation containing the variables and the "total" number. c. Focus on the phrase, "Robert has two slices of plain pizza and one slice of veggie lover's pizza for a total of 846 calories". Think about the meaning of x and y from part (a), and then write an equation containing the variables and the "total" number