# i need help on simplifying these and then classifying result by number of terms

• January 6th 2009, 08:04 PM
racerfreak05
i need help on simplifying these and then classifying result by number of terms
(2c^2+9)-(3c^2-7)
• January 6th 2009, 08:24 PM
Mush
Quote:

Originally Posted by racerfreak05
(2c^2+9)-(3c^2-7)

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

Multiply through the 2nd bracketed term by the negative!

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

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

Collect like terms:

$-c^2+16$

Change the order so the positive term is first!

$16-c^2$

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

$4^2-c^2$

$(4-c)(4+c)$