View Full Version : what is the solution set of 5y^2-16y=-3
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?
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