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Question 49118This question is from textbook Beginning Algebra
: Evaluate function for the value specified.
f(x )=x to the 2nd power-7x+10; find (a) f(0) (b) f(5) and (c) f(-2)
I do not understand what they are asking on this practice question.
This question is from textbook Beginning Algebra
Answer by Born2TeachMath(20)   (Show Source):
You can put this solution on YOUR website! What is a function? What does the function f(x)=x^2 - 7x + 10 really mean?
A function is just a formula for finding the answer anytime you know an input value. In your situation, your formula says:
#1: take the input number (called x for lack of a better name), and square it (this is what the x^2 means)
#2: take the input number, and mulitply it by 7 (this is 7x)
#3: take the number 10.
#4 take your answer to #1, subtract answer #2 from it, and then add answer #3 (the number 10)
Your answer is the answer to f(x).
That's what f(x) really means....
Therefore, what is f(0)?
Plug 0 in for x everywhere you see it in the formula f(x):
f(0) = 0^2 - 7(0) + 10
f(0) = 0 - 0 + 10
f(0) = 10
What is f(5)?
Plug 5 in for x everywhere you see it in the formula f(x):
f(5) = (5)^2 - 7(5) + 10
f(5) = 25 - 35 + 10
f(5) = 0
What is f(-2)?
Plug -2 in for x everywhere you see it in the formula f(x):
f(-2) = (-2)^2 - 7(-2) + 10
f(-2) = 4 + 14 + 10
f(-2) = 28
OK? I hope this helps.
This idea also works for things like f(t), f(2a), and f(t+1). Just plug in t, 2a, and t+1, and then simplify. You won't get a number answer, but rather a formula as an answer.
Good luck...
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