SOLUTION: If (w^4 v^5)/(u^3) is greater than 0, which of the following does not have to be positive? A. u^9 v^7 w^2 B. w^6 v^9 u^6 C. v^6 w^8 u^12 D. w^6 v^11 u^19 E. w^10 v^2 u^2

Algebra.Com
Question 1130807: If (w^4 v^5)/(u^3) is greater than 0, which of the following does not have to be positive?
A. u^9 v^7 w^2
B. w^6 v^9 u^6
C. v^6 w^8 u^12
D. w^6 v^11 u^19
E. w^10 v^2 u^2

Answer by greenestamps(13200)   (Show Source): You can put this solution on YOUR website!


We only need to count the number of negative factors in a whole expression (numerator and denominator) to determine whether the expression value is positive or negative. An even number of negative factors makes the expression value positive; an odd number makes the expression value negative.

The total number of factors in the given expression is 12; and it is given that the value of that expression is positive.

In every one of the given answer choices, there is an even number of factors of w; so the product of the factors of w is positive in every answer choice. That means the sign of the expression is always determined by the number of factors of u and v.

The sum of the numbers of factors of u and v in the given expression is 8, an even number. That means any other expression in which the sum of the factors of u and v is even will have the same sign as the given expression.

The sum of the numbers of factors of u and v in all the answer choices except B is even, so all of those answer choices must be positive.

ANSWER: The only answer choice that does not have to be positive is B.

RELATED QUESTIONS

1)u×u>=0 and u×u=0 if and only if u=0 prove theorem? 2)Show that there are no vectors u... (answered by lynnlo)
Please help me ㅠㅠ help me 1)u×u>=0 and u×u=0 if and only if u=0 prove... (answered by lynnlo)
1)u×u>=0 and u×u=0 if and only if u=0 prove theorem? 2)Show that there are no vectors u... (answered by lynnlo)
Each of angles b/t the vectors u,v,& w is 60. ||u||= 4. . ||v||=2 & ||w||=6 Then find... (answered by robertb)
It is known that the following is true. |x y z| |u v w| = 13 |1 2 3| Use properties (answered by richard1234)
u: <3, -1> v: <4, 3> w: <⅔ , -8/9 > What is the angle between v and w? A.)... (answered by KMST)
Are there any mistakes made in solving the following problem? If so, provide the correct... (answered by RBryant)
u: <3, -1> v: <4, 3> w: <⅔ , -8/9 > Which vectors involve right angles? A.) u... (answered by KMST)
(u+w)²-v²÷(v+w)²-u² (answered by robertb)