Coach decaro records the cross country runners’ times compared to their personal best times. 3k times runner time compared to personal best gregor +5.6 hiroki –11.6 isabelle +3.2 juan 0 karen –5.2 which runners ran slower than their personal best? juan gregor and isabelle gregor, isabelle, and juan hiroki and karen

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

your answer is  

a.

5

step-by-step explanation: