basic algebra help!

**mike--1988** · January 5th 2010, 09:42 AM

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..

**shinhidora** · January 5th 2010, 09:46 AM

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..

$f(x) = 2 - x^2$ where $x = -3$
$f(x) = 2-(-3)^2$
$f(x) = 2 - 9$
$f(x) = -7$

**Archie Meade** · January 5th 2010, 09:46 AM

$3(3)=3+3+3=9$

$3(-3)=-3-3-3=-9$

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

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

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

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

**bigwave** · January 5th 2010, 09:47 AM

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

**mike--1988** · January 5th 2010, 09:52 AM

thanks everyone

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