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OpenStudy (yamyam70):
3^ sqrt x +4 = 27 ^sqrt x
OpenStudy (yamyam70):
the exponent of the LHS is
OpenStudy (yamyam70):
\[\sqrt{x} + 4\]
OpenStudy (unklerhaukus):
so what do you get when you change the base of the RHS
OpenStudy (yamyam70):
(3)^3(sqrtx)
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OpenStudy (unklerhaukus):
yep, so now the bases on LHS and RHS are the same
\[\large3^{\sqrt x +4} = 3^{3\sqrt x} \]
taking the log to base three on both sides
\[\large\log_33^{\sqrt x +4} = \log_33^{3\sqrt x} \]
cancles the bases
\[\large{\sqrt x +4} = {3\sqrt x} \]
OpenStudy (unklerhaukus):
now just solve for \(x\)
OpenStudy (yamyam70):
thats the problem unkle, from that equation is it legal for this to happen
\[(\sqrt{x} + 4)^2 = (3\sqrt{x})^2\]
OpenStudy (unklerhaukus):
hmm, there is a much eaisier way
OpenStudy (yamyam70):
Please :)
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OpenStudy (unklerhaukus):
**
√x+4 = 3√x
take away √x form both sides
OpenStudy (yamyam70):
\[\sqrt{x} + 4 = 3\sqrt{x} / \sqrt{x } ??\]
OpenStudy (unklerhaukus):
√x+4 -√x = 3√x -√x
4 = (3-1)√x
OpenStudy (unklerhaukus):
{the four wasent undrer the square root was it?}
OpenStudy (yamyam70):
yep
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OpenStudy (unklerhaukus):
it was? or it wasn't?
OpenStudy (yamyam70):
it was not under the sqrt
OpenStudy (unklerhaukus):
ok good.
OpenStudy (yamyam70):
I'm a little confused about the RHS
OpenStudy (yamyam70):
oh you factored it ?
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OpenStudy (unklerhaukus):
we had
3√x -√x right?
in other terms
3 B - B
to simplify
you have to realize that the terms are common
(3-1)B
we can combine the coefficients
and simplify
..B
OpenStudy (yamyam70):
\[(4 )^2= (2\sqrt{x})^2\]
OpenStudy (yamyam70):
16 = 4x
x = 4
is it correct ?
OpenStudy (unklerhaukus):
yeah x works out to equal 4
OpenStudy (yamyam70):
Thanks again unckle ! I shall do the checking :)
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OpenStudy (unklerhaukus):
but you dont have to square the expression intill tha last step
4 = (3-1)√x
4 = 2√x
2 = √x
4 = x