If fg(x) = 2x + 1, and f(x) = x + 2, find g(5) and g-'f'(1).​

g(5) - f(1) = 8

g(5) = 11

Step-by-step explanation:

Given:

g(x) = 2x + 1

f(x) = x + 2

Find:

g(5)

g(5) - f(1)

Computation:

g(x) = 2x + 1

g(5) = 2(5) + 1

g(5) = 11

f(x) = x + 2

f(1) = 1 + 2

f(1) = 3

g(5) - f(1) =11 - 3

g(5) - f(1) = 8

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