Mathematics
6 Online
OpenStudy (anonymous):
MEDAL
f(x)=(x^2+3x-4) and g(x)=(x+4)
a) find FOG and state the domain
b) find f/g and state the domain.
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OpenStudy (anonymous):
@campbell_st @ganeshie8 @dan815 @Nnesha @wolf1728
OpenStudy (misty1212):
HI!!
OpenStudy (anonymous):
HI! Please help me!
OpenStudy (misty1212):
\[f\circ g(x)=f(g(x))\] we work from the inside out
OpenStudy (misty1212):
\[f(g(x))=f(x+4)\] is a start
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OpenStudy (anonymous):
Is for the first one x^2+11x+32 with the domain as all real numbers?
OpenStudy (misty1212):
then since
\[f(\diamondsuit)=\diamondsuit ^2+3\diamondsuit-4\] you have
\[f(x+4)=(x+4)^2+3(x+4)-4\]
OpenStudy (misty1212):
then algebra give me a sec
but the domain is all real numbers for sure
OpenStudy (anonymous):
I mean +28 at the end
OpenStudy (misty1212):
i get \((x+8) (x+3)\) or
\[x^2+11x+24\] same thing
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OpenStudy (anonymous):
Okay, and fr the second one?
OpenStudy (misty1212):
oh hold on let me see about the constant again
OpenStudy (misty1212):
24 is right
OpenStudy (anonymous):
Okay and how do I do f/g
OpenStudy (misty1212):
at the risk of sounding silly, put f over g
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OpenStudy (misty1212):
ok i copied that wrong it is
\[\frac{x^2+3x-4}{x+4}\] so the domain is all numbers except \(-4\)
OpenStudy (misty1212):
now we can factor and cancel \[\frac{(x+4)(x-1)}{x+4}=x-1\]
OpenStudy (anonymous):
Now what?
OpenStudy (anonymous):
(x-1)/1 = (x-1)?
OpenStudy (misty1212):
now go have a nice glass of wine
since we are done
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OpenStudy (anonymous):
So how would I write the solution?
OpenStudy (anonymous):
y=x-1?
OpenStudy (misty1212):
as \(x-1\) for \(x\neq -4\)
OpenStudy (anonymous):
Thank you so much!
OpenStudy (misty1212):
\[\color\magenta\heartsuit\]