Three people went to lunch. me. anderson spent a total of $13 on one entrée and 2 sides. mr. allen spent a total of $19.50 on 2 entrée and 1 side. if the lunch special made each entrée the same price (as the other entrées) and each side the same price (as the other sides), how much did hungry mr. greene spend in 3 entrées and 2 sides? set up a linear systems and solve

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

step-by-step explanation: