What is the value of x^4y^2 - x^4y^2 ?

Question

What is the value of  x^4y^2 - \frac{x^4}{y^2}  ?

(1) x = 2y

(2) y = 1

Lucky2783 · Answer

(1) x = 2y
 on substituting x=2y into  x^4y^2 - x^4/y^2  we will get an expression in Y . Not sufficient.

(2) At y = 1 
 x^4y^2 - x^4/y^2  = 0 Sufficient. answer :B

mvictor · Answer

x^4y^2 - x^4/y^2 ?

written in this form, we get
x^(4y^2) which is x^16y
(1) doesn't tell much 
(2) from x^16y we substract x^4, since y^2 =1
I guess something is missing here..
it is not clear whether (x^4)*(y^2) or that 4y^2 is the exponent of x.
if it is the first option, then the answer is B
if it is the second one, then the answer is E.

FightToSurvive · Answer

On further simplification of the problem we get , x^(8y) - x^(8/y)

St 1 gives a unkown variable. Not Sufficient.
St 2 solves the unknown. Sufficient.

Answer: B

peachfuzz · Answer

Statement 1: 
after substituting 2y for x, we are still left with y
Insufficient

Statement 2:
when y=1, the expression equates to 0
Sufficient

Answer: B

chetan2u · Answer

hi, 
you will have to check on the equation you get after simplifying...

lipsi18 · Answer

X^4Y^2-x^4/Y^2

1. X=2Y; substituting values equation will be in one variable 2Y^4Y^2-2Y^4/Y^2, but value of y is still unknown, not sufficient

2. y=1, X^4-X^4=0; sufficient

Hence answer is B

Thanks,

Bunuel · Answer

MAGOOSH OFFICIAL SOLUTION: evaluationwexpo_explanation.png

fskilnik · Answer

?\,\,\,\, = \,\,\,\,{x^4}{y^2} - {{{x^4}} \over {{y^2}}}\,\,\,\, = \,\,\,\,{x^4}\left( {{y^2} - {1 \over {{y^2}}}} ight)

\left( 1 ight)\,\,x = 2y\,\,\,\,\left\{ \matrix{
 \,{m{Take}}\,\,\left( {x,y} ight) = \left( {2,1} ight)\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,? = \,\,\,{2^{\,4}}\left( {1 - 1} ight) = 0 \hfill \cr 
 \,{m{Take}}\,\,\left( {x,y} ight) = \left( {4,2} ight)\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,? = \,\,\,{4^{\,4}}\left( {4 - {1 \over 4}} ight) 
e 0\,\, \hfill \cr} ight.

\left( 2 ight)\,\,y = 1\,\,\,\,\, \Rightarrow \,\,\,\,\,\,?\,\, = \,\,{x^4} \cdot \left( {1 - {1 \over 1}} ight)\,\, = \,\,0\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,{m{SUFF}}.\,\,\,\,\,\,

This solution follows the notations and rationale taught in the GMATH method.

Regards, 
Fabio.

What is the value of x^4y^2 - x^4y^2 ?

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What is the value of x^4y^2 - x^4y^2 ?

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