sally found 71 seashells on the beach she gave benny some of her seashells. she has 32 seashells lefts. how many seashells did she give to benny part a: write the equation

39

Step-by-step explanation:

71-32=x

or

71-x=32

Step-by-step explanation:

x represents how many seashells she gave benny.

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