Mathematics
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OpenStudy (anonymous):
using the quadractic formula solve 3x^2-17=0
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hartnn (hartnn):
Compare your quadratic equation with \(ax^2+bx+c=0\)
find a,b,c
then the two roots of x are:
\(\huge{x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}}\)
hartnn (hartnn):
can u find a,b,c ?
OpenStudy (anonymous):
no
hartnn (hartnn):
a=3,b=0,c=-17
now just put these in the formula i gave ....
OpenStudy (anonymous):
oh ok i get it now
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hartnn (hartnn):
good, so what 2 values of x u got ?
OpenStudy (anonymous):
i got 2.38 and -2.38
hartnn (hartnn):
that is correct!
good work :)
OpenStudy (anonymous):
how about this equation 2y^2=-5y
hartnn (hartnn):
here a=2, b= 5,c=0
do u get how ?
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OpenStudy (anonymous):
so would the answers be 2.28 and .22
OpenStudy (anonymous):
in the back of the book they have -5/2,0
hartnn (hartnn):
do u need to use formula ? because there is simpler way for 2y^2=-5y
OpenStudy (anonymous):
in the book it says that you do
hartnn (hartnn):
so did u get how a=2, b= 5,c=0
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hartnn (hartnn):
then u just put these in formula
OpenStudy (anonymous):
i did put them in the formula but how do you get -5/2 and 0?
hartnn (hartnn):
ok, what u got b^2-4ac as ?
hartnn (hartnn):
5^2-4*2*0 = ?
OpenStudy (anonymous):
yes i have that
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hartnn (hartnn):
so what numerator u got ?
hartnn (hartnn):
the denominator =2a=4
hartnn (hartnn):
\(\large -b+\sqrt{b^2-4ac}=-5+\sqrt{25-0}=-5+5=0\)
did u get this ?
hartnn (hartnn):
so one of the root = 0
hartnn (hartnn):
\(\large -b-\sqrt{b^2-4ac}=-5-\sqrt{25-0}=-5-5=-10\)
and with denominator =4, u get other root as -10/1 = -2/5
got this ?
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hartnn (hartnn):
*-10/4=-5/2
OpenStudy (anonymous):
ok
hartnn (hartnn):
good, any more doubts ?
OpenStudy (anonymous):
no that is it
OpenStudy (anonymous):
thanks
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hartnn (hartnn):
welcome ^_^