<p>If a>1 in the equation (a^x)/(a^y)=a^-6
and a^x * a^y= a^12 what is the value of y?</p>
<p>i don't get it..the answer key says 4 but i keep on getting y=9 ..am i wrong or is the answerkey wrong?
thnxs =]</p>
<p>exponents
x - y = -6; x = y - 6
x + y = 12</p>
<p>(y - 6) + y = 12
2y - 6 = 12
2y = 18
y = 9</p>
<p>testing it.
(a^x)/(a^9)=a^-6; x has to be 3.
second equation
a^3 * a^9= a^12. </p>
<p>9 is correct.</p>
<p>i'll second him ^^
it has to be nine
y=4 does not work
x would have to be 8 in order for the second part to work, but 8-4 =/= -6 </p>
<p>9 should be the correct answer. book screwed up :O</p>
<p>Yeah, the answer was definiltely misprinted. What book are you using?</p>
<p>its actually not a book..its more like a packet..i go to this test prep place..its kinda stupid -_-</p>