SOLUTION: f(x)=(3x^2)+5 If t is a number find f(t+1) and f(t-1) Simplify your answers. I am totally lost. :( Please help, thanks!

Algebra ->  Functions -> SOLUTION: f(x)=(3x^2)+5 If t is a number find f(t+1) and f(t-1) Simplify your answers. I am totally lost. :( Please help, thanks!      Log On


   

Question 707866: f(x)=(3x^2)+5
If t is a number find f(t+1) and f(t-1) Simplify your answers.
I am totally lost. :( Please help, thanks!
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
Here is how to find your way:

replace the variable, x, with the number t+1, and replace the variable, x, with the number t-1. Evaluate the function for each case. The key idea is to use substitution.

f%28t%2B1%29=%283%28t%2B1%29%5E2%29%2B5
=3%28t%5E2%2B2t%2B1%29%2B5
=3t%5E2%2B6t%2B3%2B5
=3t%5E2%2B6t%2B8, and maybe you complete the square to get standard form if you wish to.
That was for x=t+1.

Now do the same using t-1 in place of x.
f%28t-1%29=%283%28t-1%29%5E2%29%2B5,
...and you know what to do...