SOLUTION: The book gives an example of a function for X that substituts 1/2 for X in the expression.... f(1/2)=(1/2)^3 - 3(1/2)^2 + (1/2) + 5 =1/8 - 3(1/4) + 1/2 + 5 =1/8 - 3/4 + 1/

Algebra ->  Functions -> SOLUTION: The book gives an example of a function for X that substituts 1/2 for X in the expression.... f(1/2)=(1/2)^3 - 3(1/2)^2 + (1/2) + 5 =1/8 - 3(1/4) + 1/2 + 5 =1/8 - 3/4 + 1/      Log On


   



Question 146614: The book gives an example of a function for X that substituts 1/2 for X in the expression....
f(1/2)=(1/2)^3 - 3(1/2)^2 + (1/2) + 5
=1/8 - 3(1/4) + 1/2 + 5
=1/8 - 3/4 + 1/2 +5
=1/8 - 6/8 +4/8 + 40/8
= 39/8
Now im sure this is just simple addition and subtraction with fractions, but I haven't worked with math in many years.
Can someone break down
f(X) = 2X^3 - X^2 + 3X - 2
with f(-1/2) substuting for X please, the more info the better.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+2x%5E3-x%5E2+%2B+3x-2
f%28-1%2F2%29+=+2%28-1%2F2%29%5E3-%28-1%2F2%29%5E2+%2B+3%28-1%2F2%29-2
f%28-1%2F2%29+=+2%28-1%2F8%29-%281%2F4%29+-+%283%2F2%29-2
To add and subtract fractions, you need to have a common denominator.
Change all fraction to common denominator of 8.
1%2F4=2%2F8
3%2F2=12%2F8
2=16%2F8
f%28-1%2F2%29+=+2%28-1%2F8%29-%281%2F4%29+-+%283%2F2%29-2
f%28-1%2F2%29+=+%28-2%2F8%29-%282%2F8%29+-+%2812%2F8%29-16%2F8
f%28-1%2F2%29+=+%28-2-2-12-16%29%2F8
f%28-1%2F2%29+=+%28-32%29%2F8
f%28-1%2F2%29+=+-4