Mathematics
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OpenStudy (anonymous):
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OpenStudy (anonymous):
Simultaneous equations
OpenStudy (anonymous):
\[\huge \sqrt{a}+b=7\]
\[\huge \sqrt{b}+a=11\]
OpenStudy (anonymous):
Solve for a and b
OpenStudy (anonymous):
Each time i try with a different method i get different answers
hartnn (hartnn):
not sure whthert there is a shortcut,
but the long way to do is by using elimination
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hartnn (hartnn):
a= (7-b)^2
plug it in 2nd equation
then square it,
you will get a 4th degree polynomial in 'b'
that gives you 4 values of b
OpenStudy (anonymous):
I tried it , i am getting a quadratic how do i put it under the root :0
OpenStudy (anonymous):
there are two whole number sollutions for this
hartnn (hartnn):
sqrt b = 11 - (7-b)^2
square it now
OpenStudy (anonymous):
one more thing i tried is to find the ratio between a and b yes wait
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OpenStudy (anonymous):
b = 11 -49-14b+b^2
hartnn (hartnn):
a= 9, b =4
easy to eyeball
OpenStudy (anonymous):
yeah , the question says that no trial and error :)
hartnn (hartnn):
b = 11 -49-14b+b^2 <<<incorrect
hartnn (hartnn):
still incorrect :P
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hartnn (hartnn):
b= (11- (7-b)^2)^2
OpenStudy (anonymous):
Ok i didn't see the root forget it
OpenStudy (anonymous):
so 4th degree plynimial creeping there
OpenStudy (anonymous):
i don't know if it helps but
i got 5/3 = a/b
hartnn (hartnn):
thats incorrect, right ?
given that one of the solution is 9,4
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OpenStudy (anonymous):
checked it again getting the same thing
OpenStudy (anonymous):
maybe beacuse there is a root so extra sollution
OpenStudy (anonymous):
i really don't know
OpenStudy (anonymous):
I multiplied 1 st equation by a
second by b
OpenStudy (anonymous):
and subtracted
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OpenStudy (anonymous):
argh silly mistakes i am making tdae
OpenStudy (anonymous):
the first step is the culprit
hartnn (hartnn):
lets think of a different approach....or solve that duadric eq.
hartnn (hartnn):
*quadric
OpenStudy (anonymous):
there must be a different approach to this
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hartnn (hartnn):
a and b must be perfect squares
b must be less than 7
which gives b must be 1 or 4
b=1, makes a imperfect square
OpenStudy (anonymous):
great !
hartnn (hartnn):
provided a and b are real