(2c^2+9)-(3c^2-7)

- Jan 6th 2009, 07:04 PMracerfreak05i need help on simplifying these and then classifying result by number of terms
(2c^2+9)-(3c^2-7)

- Jan 6th 2009, 07:24 PMMush
$\displaystyle (2c^2+9)-(3c^2-7) $

Multiply through the 2nd bracketed term by the negative!

$\displaystyle (2c^2+9)-3c^2-(-7) $

$\displaystyle 2c^2+9-3c^2+7 $

Collect like terms:

$\displaystyle -c^2+16 $

Change the order so the positive term is first!

$\displaystyle 16-c^2 $

Recognise that this is a difference of two squares since $\displaystyle 16 = 4^2 $:

$\displaystyle 4^2-c^2 $

$\displaystyle (4-c)(4+c) $