eviant:

Let f(x) = -2x - 7 and g(x) = -4x + 6. Find (f*g)(-5)

3 weeks ago
eviant:

@mhchen

3 weeks ago
mhchen:

I think (f*g)(-5) = f(-5)*g(-5). so first find f(-5)

3 weeks ago
eviant:

10x+35

3 weeks ago
mhchen:

uh well f(-5) = -2(-5) - 7 = 10 - 7 = 3

3 weeks ago
mhchen:

I'm not sure how you got 10x + 35, Did you see what I did? Try to find g(-5) now,

3 weeks ago
eviant:

-4(-5)+6 20+6 26?

3 weeks ago
mhchen:

Yup so all you have to do now is multiply f(-5) and g(-5) together 3 * 26

3 weeks ago
eviant:

78?

3 weeks ago
mhchen:

ye

3 weeks ago
eviant:

3 –6 26 –59

3 weeks ago
mhchen:

oh are those the options?

3 weeks ago
eviant:

^^those are the choices

3 weeks ago
mhchen:

HMMMmmmmm

3 weeks ago
mhchen:

okay I'm gonna assume (f*g)(x) is (fog)(x) or f(g(x)) a composite function

3 weeks ago
mhchen:

basically first you find g(-5) which you already did. It was 26 Then you plug 26 into f(x)

3 weeks ago
mhchen:

Can you find f(26)?

3 weeks ago
eviant:

@mhchen -2(26)-7=-59?

3 weeks ago
mhchen:

yep

3 weeks ago