SOLUTION: Evaluate h(x) = 6x+9 and f(x)=8x^2-4 a) f(-3)-h(-3) b) (f+h)(2) c) (foh)(x) d) (hof)(x) This is confusing.Thank you for your help

Algebra ->  Rational-functions -> SOLUTION: Evaluate h(x) = 6x+9 and f(x)=8x^2-4 a) f(-3)-h(-3) b) (f+h)(2) c) (foh)(x) d) (hof)(x) This is confusing.Thank you for your help      Log On


   



Question 1036083: Evaluate
h(x) = 6x+9 and f(x)=8x^2-4
a) f(-3)-h(-3)
b) (f+h)(2)
c) (foh)(x)
d) (hof)(x)
This is confusing.Thank you for your help

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
f(-3)=8(-3)^2-4=68
h(-3)=6(-3)+9=-9
Their difference is 59. A
f+h=8x^2+6x+5. Substitute (2) is for x, and the result is 32+12+5=49 B
(f o h)(x) is f(h(x). But h(x)=6x=9. that is substituted for each x in f.
That is 8(6x+9)^2-4=8(36x^2+108x+81)-4, or 288x^2+864x+644
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(h o f)(x)=h (f(x)) and substitute f(x) for the x in h(x)
6(8x^2-4)+9=48x^2-15