How many real roots does the equation x^4y+16xy+64y=0 have if y < 0? Select
A) 0 B) 1 C) 2 D) 3 E) Infinite
x^4y+16xy+64y=0   =&gt; y ( x^2 + 16x + 64) = 0   =&gt; y (x+8)^2 = 0   if y&lt;0 , then x=-6   So although there are 2 factors , they are the same x=-6 .   The equations has 3 distinct real root .   Answer 3
<result>D</result>
How many real roots does the equation x^4y+16xy+64y=0 have if y < 0?