SOLUTION: Please help. For f(x)=-3x^2 +5x-6, find (a) f(-2) (b)f(1/b)

Algebra ->  Functions -> SOLUTION: Please help. For f(x)=-3x^2 +5x-6, find (a) f(-2) (b)f(1/b)      Log On


   

Question 883943: Please help.
For f(x)=-3x^2 +5x-6, find (a) f(-2) (b)f(1/b)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=-3x%5E2%2B5x-6


f%28-2%29=-3%28-2%29%5E2%2B5%28-2%29-6 Replace every x with -2


f%28-2%29=-28 Evaluate (with a calculator)


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For part b, plug in x = 1/b and simplify to get


f%28x%29=-3x%5E2%2B5x-6


f%281%2Fb%29=-3%281%2Fb%29%5E2%2B5%281%2Fb%29-6


f%281%2Fb%29=-3%281%2F%28b%5E2%29%29%2B5%281%2Fb%29-6


f%281%2Fb%29=-3%2F%28b%5E2%29%2B5%2Fb-6


f%281%2Fb%29=-3%2F%28b%5E2%29%2B%285b%29%2Fb-%286b%5E2%29%2F%28b%5E2%29


f%281%2Fb%29=%28-3%2B5b-6b%5E2%29%2F%28b%5E2%29


f%281%2Fb%29=%28-6b%5E2%2B5b-3%29%2F%28b%5E2%29