Find the LCM of each set of polynomials. If needed, show work and explain.
19. x^2 - y^2, x^3 + x^2 y

Question

Find the LCM of each set of polynomials. If needed, show work and explain. 
19. x^2 - y^2, x^3 + x^2 y

firejay5 · Answer

http://www.wolframalpha.com/input/?i=lcm+of+x^2+-+y^2%2C+x^3+%2B+x^2y

firejay5 · Answer

What would the answer be clicking the following link to wolframalpha???

anonymous · Answer

the first one factors as $(x+y)(x-y)$ and the second one factors as $x^2(x+y)$

anonymous · Answer

so the lcm is 
$$x^2(x+y)(x-y)$$

firejay5 · Answer

@satellite73 Thanks! Bro! :D

firejay5 · Answer

@phi  Why wouldn't it be x^2(x + y) (x + y) (x - y)

firejay5 · Answer

@robtobey

phi · Answer

your version x^2(x + y) (x + y) (x - y)
can be divided by both  x^2 - y^2, and by x^3 + x^2 y 
That means your answer is a multiple of those two expressions

however, notice if we take out (x+y) from your answer
x^2(x + y) (x - y)

both  x^2 - y^2, and  x^3 + x^2 y still divide into it.
your answer is not the *least*.