02 Sep 2014
Algebra question- how do I solve an equation by factoring?
I have another different problem I can't use that zero method for. y^2-4y=21?
I can't figure it out!
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Answer
No
Submitted by admin on Tue, 09/02/2014 - 11:24
I dont Know
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To find delta
Submitted by admin on Tue, 09/02/2014 - 10:30
y^2-4y=21 is the same thing as y^2-4y-21=0. then you use delta to find the root(s) (roots = solution).
To find delta: if you have an equation like this: ax^2 + bx + c = 0 (which is your case), delta= b^2 - 4*a*c
-> if delta is negative, the equation has no root
-> if delta = 0, you have one root, which equals to -b/2a
-> if delta is positive, you have two roots, which are [-b -sqrt(delta)]/2a and [-b +sqrt(delta)]/2a
sqrt = square root
I hope this was clear, good luck :)
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