SOLUTION: f(x)=x^2 + 3 and g(x) = -2x + 6 Find (fg)(4) Find (f+g)(3) Find (f/g)(5) Find (f-g)(4) Find (f+g)(-5)

Algebra ->  Functions -> SOLUTION: f(x)=x^2 + 3 and g(x) = -2x + 6 Find (fg)(4) Find (f+g)(3) Find (f/g)(5) Find (f-g)(4) Find (f+g)(-5)      Log On


   

Question 1090187: f(x)=x^2 + 3 and g(x) = -2x + 6
Find (fg)(4)
Find (f+g)(3)
Find (f/g)(5)
Find (f-g)(4)
Find (f+g)(-5)
Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
Find (fg)(4)
I way: (fg)(x)=%28x%5E2%2B3%29%28-2x%2B6%29=-2x%5E3%2B6x%5E2-6x%2B18
(fg)(4)=-2%2A4%5E3%2B6%2A4%5E2-6%2A4%2B18=-38
II way: f%284%29=4%5E2%2B3=19
g%284%29=-2%2A4%2B6=-2
fg%284%29=19%2A%28-2%29=-38
.
Find (f+g)(3)
f%283%29=3%5E2%2B3=12
g%283%29=-2%2A3%2B6=0
(f+g)(3)=12%2B0=12
.
Find (f/g)(5)
f%285%29=5%5E2%2B3=28
g%285%29=-2%2A5%2B6=-4
(f/g)(5)=28%2F-4=-7
.
Find (f-g)(4)
f%284%29=4%5E2%2B3=19
g%284%29=-2%2A4%2B6=-2
%28f-g%29%284%29=19-%28-2%29=21
.
Find (f+g)(-5)
f%28-5%29=%28-5%29%5E2%2B3=28
g%28-5%29=-2%2A%28-5%29%2B6=16
(f+g)(-5)=28%2B16=44