If x and y are positive integers such that the greatest common factor of x^2y^2 and xy^3 is 45, then which of the following could y equal?

A. 45
B. 15
C. 9
D. 5
E. 3

Respuesta :

Answer:

Option E.

Step-by-step explanation:

The given expressions are [tex]x^2y^2[/tex] and [tex]xy^3[/tex].

[tex]x^2y^2=x\times x\times y\times y[/tex]

[tex]xy^3=x\times y\times y\times y[/tex]

Greatest common factor of [tex]x^2y^2[/tex] and [tex]xy^3[/tex] is

[tex]GCF=x\times y\times y=xy^2[/tex]

It is given that the greatest common factor of  [tex]x^2y^2[/tex] and [tex]xy^3[/tex] is 45.

[tex]xy^2=45[/tex]

[tex]x=\dfrac{45}{y^2}[/tex]

x and y are positive integers.

For y=45,15,9,5 [tex]x=\dfrac{45}{y^2}\notin Z^+[/tex]

Only for y=3,

[tex]x=\dfrac{45}{3^2}[/tex]

[tex]x=\dfrac{45}{9}[/tex]

[tex]x=5 \in Z^+[/tex]

The possible value of y is 3.

Therefore, the correct option is E.