Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm.
How is this problem done?
IF f(x)=2x^2-8x-3 FIND f(-2)
algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm
Put in for x the value -2, and compute f(-2)
algebra 2 - hellogoodbie, Saturday, January 16, 2010 at 1:47pm
so is the answer f=21/2? if that is right, thank you bobpursley
algebra 2 - drwls, Saturday, January 16, 2010 at 3:02pm
The answer has to be an integer. In this case, it is 2*4 - 8*(-2) - 3 = 21
algebra 2 - hellogoodbie, Saturday, January 16, 2010 at 3:06pm
where did u get the 4 from?
The four came from (x2)
two squared is 4
Wow, I'm so confused. Can somebody just solve this problem step by step please?
This is pretty basic. I suggest a tutor.
To find f(-2) for the function f(x) = 2x^2 - 8x - 3, you simply substitute -2 for x in the equation and compute the value.
Here's how you can do it step by step:
1. Start with the function f(x) = 2x^2 - 8x - 3.
2. Replace x with -2: f(-2) = 2(-2)^2 - 8(-2) - 3.
3. Simplify the expression inside the parentheses: f(-2) = 2(4) + 16 - 3.
4. Multiply: f(-2) = 8 + 16 - 3.
5. Combine like terms: f(-2) = 24 - 3.
6. Subtract: f(-2) = 21.
Therefore, f(-2) is equal to 21.
The answer provided by hellogoodbie, 21/2, is incorrect. The correct answer, as given by drwls, is 21.