Mathematics
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OpenStudy (anonymous):
Please & thank you!
Use properties of logarithms to solve the equation.
log(base3) x + log(base3)(x + 2) = log(base3) 2 + log(base3) 12
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OpenStudy (anonymous):
as i can recall log(ab)=loga+logb
use this property
OpenStudy (anonymous):
i dont understand how to solve it though
mathslover (mathslover):
\[\large{log_3 x+log_3 (x+2)=log_3 2+log_3 {12}}\]
mathslover (mathslover):
\[\large{log_3(x(x+2))=log_3(2*12)}\]
mathslover (mathslover):
x(x+2) = 24
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mathslover (mathslover):
can you solve further?
OpenStudy (anonymous):
would the answer just be be one?
mathslover (mathslover):
just tell me what is x(x+2)
OpenStudy (anonymous):
x^2 + 2x
mathslover (mathslover):
\[\large{x^2+2x-24=0}\]
\[\large{x^2+6x-4x-24=0}\]
\[\large{x(x+6)-4(x+6)=0}\]
\[\large{(x-4)(x+6)=0}\]
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mathslover (mathslover):
hence we have x = 4 or x = -6
OpenStudy (anonymous):
why is it -24 and not just 24
mathslover (mathslover):
x^2+2x=24
right?
mathslover (mathslover):
now subtract 24 both sides
x^2+2x-24=24-24
x^2+2x-24=0
OpenStudy (anonymous):
oh okay! thank you!
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mathslover (mathslover):
no problem and best of luck
OpenStudy (anonymous):
thanls
OpenStudy (anonymous):
but remember only the positive answer is accepted
OpenStudy (anonymous):
would it be wrong if i gave the negative answer as well?
mathslover (mathslover):
yes