1. basic algebra help!

this is a simple question but its confused me
heres the question

f(x)= 2 - x^2 where x = -3

is it -7 or is it 11 im confused by the sign change

thanks..

2. Originally Posted by mike--1988
this is a simple question but its confused me
heres the question

f(x)= 2 - x^2 where x = -3

is it -7 or is it 11 im confused by the sign change

thanks..
$\displaystyle f(x) = 2 - x^2$ where $\displaystyle x = -3$
$\displaystyle f(x) = 2-(-3)^2$
$\displaystyle f(x) = 2 - 9$
$\displaystyle f(x) = -7$

3. $\displaystyle 3(3)=3+3+3=9$

$\displaystyle 3(-3)=-3-3-3=-9$

$\displaystyle (-3)(-3)=-[3(-3)]=opposite\ of\ subtract\ 3\ three\ times$

$\displaystyle which\ is\ add\ 3\ three\ times.$

$\displaystyle Hence\ (-3)(-3)=3(3)=9$

$\displaystyle 2-x^2=2-(-3)^2=2-(9)=-7$

4. Originally Posted by mike--1988
this is a simple question but its confused me
heres the question

f(x)= 2 - x^2 where x = -3

is it -7 or is it 11 im confused by the sign change

thanks..
f(-3) = 2 -(-3)^2 = -7

5. thanks everyone