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Mathematics 16 Online
OpenStudy (dtan5457):

What is the value of x in the equation?

OpenStudy (dtan5457):

\[(81)^{x+2}=27^{5x+4}\]

OpenStudy (mathstudent55):

If you can write an equation of one power equaling another power, and the bases are equal then the exponents are equal. For example, if \(a^x = a^y\) Then x = y Ok so far?

OpenStudy (dtan5457):

Yes

OpenStudy (mathstudent55):

Notice in this case that both 81 and 27 are powers of 3. Rewrite the equation as two powers of 3 that are equal to each other. Then the exponents are equal. Then solve for x.

OpenStudy (dtan5457):

Got it (3^4)^x+2=(3^3)^5x+4 4x+8=15x+12 x=-4/11

OpenStudy (mathstudent55):

\((3^4)^{x+2}=(3^3)^{5x+4}\)

OpenStudy (mathstudent55):

Correct.

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