Question

HELP PLEASE @mathstudent55
Consider the functions f(x) = 2x + 1 and g(x) = x2 − 10. What is the value of f[g(3)]?

39

−3

−7

−1

Answer 1

First...what is g(3)? *plug 3 in for every 'x' you see in the equation*

Answer 2

Im not sure

Answer 3

g(x) = x² - 10

What you do *because you want g(3) is replace every 'x' you see with a 3...so

g(3) = (3)² - 10
g(3) = 9 - 10
g(3) = ?

Answer 4

-1

Answer 5

So d

Answer 6

Right -1 ...so now......What you do...is take that -1 ....and plug it in for 'x' in your f(x) equation

f(x) = 2x + 1

f(-1) = 2(-1) + 1

f(-1) = -2 + 1

f(-1) = ???

Answer 7

-3

Answer 8

That my answer

Answer 9

Not quite...remember -2 + 1....you are adding 1 to -2 so it becomes -1 right?

Answer 10

-1 sorry

Answer 11

Can you help with two more questions please?

Answer 12

No problem! Good work!

So in general...with an f(g(number)) problem like that....

1) solve for g(number)
2) take that answer and plug it into the 'f' equation for 'x'
3) solve that and you have your answer

Answer 13

Consider the functions f(x) = 3x − 2 and g(x) = x2 − 1. What is the value of (f − g)(−2)?

−8

−5

−11

3

Answer 14

Okay now you take each equation seperatly and solve it with (-2) in place of 'x'

f(x) = 3x - 2
f(-2) = 3(-2) - 2
f(-2) = -6 - 2
f(-2) = ???

and

g(x) = x² - 1
g(-2) = (-2)² - 1
g(-2) = 4 - 1
g(-2) = ???

Then ...once you solve those...you take what you got from 'f'...and what you got from 'g'....and subtract them...

Answer 15

So 3

Answer 16

One More please

Answer 17

Choose the best description of how to calculate f[g(3)] if f(x) = 3x − 2 and g(x) = x2 − 1.

Calculate f(3) and g(3), then multiply them together.

Calculate f(3) and g(3), then write the results as an ordered pair.

Calculate f(3) and g(3), then subtract them.

Calculate g(3), plug the result into f(x) and simplify.

Answer 18

I don't get 3 for the first one.... and for this new one...what did we do above before???

Answer 19

What do you get for f(-2) and what do you get for g(-2) ??

Answer 20

SO 3 isnt the anser

Answer 21

From earlier

Answer 22

No...like I asked....what do you get for 'f' and for 'g' when you do

f(x) = 3x - 2
f(-2) = 3(-2) - 2
f(-2) = -6 - 2
f(-2) = ???

and

g(x) = x² - 1
g(-2) = (-2)² - 1
g(-2) = 4 - 1
g(-2) = ???

Answer 23

Im still lost

Answer 24

So 3