if f(x)=9x(cubed) +9x(squared)-x+c and f(-3)=1. whats the value of C

Question

zehanz · Answer

$$f(x)=x^3+9x^2-x+c$$$$f(-3)=(-3)^3+9(-3)^2--3+c=1$$Now do the calculations (without calculator, of course!) and solve for c!

anonymous · Answer

i get confused at the end.. because i got -27-81+3+c, right?

anonymous · Answer

-105+c?

abb0t · Answer

Integrate the function with respect to x!

zehanz · Answer

Sorry, typo :(

$$f(x)=9x^3+9x^2-x+c$$$$f(-3)=9(-3)^3+9(-3)^2--3+c=1$$

So it's 9*27+9*9+3+c=1
243+81+3+c=1
...
...

anonymous · Answer

-326?

zehanz · Answer

yup

anonymous · Answer

Nope.  c = 160
$$9(-3)^3+9(-3)^2-(-3)+c=1 $$$$9(-27)+9(9)+(3)+c=1 $$$$-243+81+3+c=1$$$$-243+84+c=1$$$$-159+c=1$$$$c=160$$

Refer to the attachment for a solution using Mathematica.

zehanz · Answer

Mathematica seems overkill to me ;)
I admit it had to be -243 instead of 243, so the final answer is 160.
And then I had the nerve to say do not use a calculator...
Well, if the numbers are more than 100 away from 0 then I'd better use the damn thing!

anonymous · Answer

Well look at this way: should NASA have hired 10,000 math slaves doing pencil and paper hand calculations to support the space shuttle flights in real time?  Without pre-programmed computers, and fast ones at that, no space program.