# need help in solving exponents

• Jun 29th 2007, 02:47 PM
lizard4
need help in solving exponents
what expression raised to the fourth power is 81?
x with exponent 12
y with exponent 8
z with exponent 12:)
• Jun 29th 2007, 02:56 PM
Plato
Quote:

Originally Posted by lizard4
what expression raised to the fourth power is 81?
x with exponent 12
y with exponent 8
z with exponent 12:)

That makes no sense!
Can you expand on that question?
• Jun 29th 2007, 03:07 PM
Ilaggoodly
the 4th root of 81 is 3, so the equation must equal 3 or -3, the r est of your question is nonsensical as plato pointed out
• Jun 29th 2007, 03:08 PM
lizard4
Dear Pluto
What expression raised to the fourth power is 81x12y8x16
12,8, and 16 are exponents[FONT='Calibri','sans-serif']

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• Jun 29th 2007, 03:13 PM
Jhevon
Quote:

Originally Posted by lizard4
What expression raised to the fourth power is 81x12y8x16
12,8, and 16 are exponents

that is nothing like the original equation, even some of the powers are different and there is no z, make sure you're not making a typo.

do you mean \$\displaystyle 81x^{12} y^8 z^{16}\$?

if so, the answer is \$\displaystyle 3 x^3 y^2 z^4\$

when we raise products to a power, we multiply the powers by the power we are raising to, that is, \$\displaystyle (xy)^n = x^n y^n\$. with that knowledge in mind, we simply take out a factor of four from the powers of all the expressions, since if we raise this new expression to the power four, we would multiply all the powers by 4 and get back the expression we started with