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nae
06-28-2006, 12:46 PM
5y^2-16y=-3
i know it has to be in standard form which is
5y^2-16+-3=0
5y^2-15+1y+-3

This is where i get lost?

tkhunny
06-28-2006, 01:39 PM
5y^2-16y=-3
i know it has to be in standard form which is
5y^2-16+-3=0
5y^2-15+1y+-3

This is where i get lost?1) Where did the equal sign go?
2) Where did the "y" go?
3) Why didn't the "-3" change signs?

5y^2 - 16y = -3

Add 3

5y^2 - 16y + 3 = -3 + 3

Simplify

5y^2 - 16y + 3 = 0

Are we factorign by grouping, or what?

5y^2 - 15y - y + 3 = 0 <== This is almost magical. Why would you do this unless you knew where it was going?

Common 5 in the first two terms. Watch the signes on the second two terms.

5(y^2 - 3y) - (y - 3) = 0

Common y in the first two terms.

5y(y - 3) - (y - 3) = 0

Common (y-3) in each term -- Watch very carefully.

(5y - 1)(y - 3) = 0

Now what? Are we solving or just factoring?