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klmjnmkj:

math problem

klmjnmkj:

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klmjnmkj:

@snowflake0531

snowflake0531:

@florisalreadytaken

geerky42:

Solution will be a little ugly, but firstly we want to bring variable \(x\) back to base. Any idea? Hint: https://www.rapidtables.com/math/algebra/logarithm/Logarithm_Rules.html#power%20rule

Florisalreadytaken:

ok, i told u am busy right -- thats why am replying late were given: \[5^{x-3}=7^x\] lets turn that into a log expression \[ x-3 = \log_5(7) \ x \] \[ \ \ \ \ \ \ \ \Updownarrow \] \[ x= \log_5(7) \ x +3 \] 3 is the constant, so we want to move the expression to the left side(opposite operator): \[ x-\log_5(7) \ x =3 \] any clue what were doing next?

klmjnmkj:

sorry i have no clue

Florisalreadytaken:

you remember we did something similar to this a while ago -- just that the numbers are different -- factor x out how would that be?

klmjnmkj:

factor x out?

Florisalreadytaken:

yes \[ \color{lightskyblue}{x}-\log_5(7) \ \color{lightskyblue}x =3 ​\] \[ \ \ \ \ \ \ \ \ \ \Updownarrow \] \[ (1-log_5(7))x = 3 \] from here its easier -- whats our next step?

klmjnmkj:

factor out 7?

Florisalreadytaken:

what? no -- that makes no sense as the previous person said, we have to leave x on its own, as its the base. to do that we have to divide both sides by \( 1-log_5(7) \) (we tool the paranthesis off as we dont need them anymore) so that means: \[ x= \frac{3}{1-log_5(7) } \]

Florisalreadytaken:

from here we cannot do anything, except using a calculator -- find the nuber, and round it to its nearest TENTH.

klmjnmkj:

-14.3

Florisalreadytaken:

yeah that looks right

klmjnmkj:

are you sure because i didnt round it

Florisalreadytaken:

what do you mean?

klmjnmkj:

i didnt round it

Florisalreadytaken:

show me your calculations please

klmjnmkj:

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Florisalreadytaken:

-14.3 correctly rounded .... what do u mean by "i didnt round it"?

klmjnmkj:

i didnt round it i just rote -14.3

Florisalreadytaken:

right, do u know what rounding is?

klmjnmkj:

yes

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