document.write( "Question 472220: If (x^2)(y^3)(z^5) is positive, which product is always positive?\r
\n" ); document.write( "\n" ); document.write( "A) xz
\n" ); document.write( "B) (y^2)z
\n" ); document.write( "C) yz
\n" ); document.write( "D) xy
\n" ); document.write( "E) y(z^2)\r
\n" ); document.write( "\n" ); document.write( "Please explain how I could approach this probelem (ie. plugging in numbers...?) and why the answer is correct.\r
\n" ); document.write( "\n" ); document.write( "Thanks!
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Algebra.Com's Answer #323790 by richard1234(7193)\"\" \"About 
You can put this solution on YOUR website!
Assuming x,y,z are real numbers not equal to zero, we can say that x^2 is always positive, so x can be either positive or negative. This, however, eliminates choices A and D from always being positive, because if z or y were positive, x could be negative, and vice versa.\r
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\n" ); document.write( "\n" ); document.write( "We can infer that (y^3)(z^5) is always positive. Hence, y and z must have the same sign. This eliminates choices B and E, because squares are always positive (in this case), and y or z could be negative. This leaves answer choice C as our only option (which must be positive anyway, because y,z have the same sign).
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