Find all zeros of 2x^4-5x^3+53x^2-125x+75=0
a.-1,-3/2,+-5i c.1,3/2,+-5
b.1,3/2,+-5i d.-1,-3/2,+-5

Question

Find all zeros of 2x^4-5x^3+53x^2-125x+75=0 
a.-1,-3/2,+-5i                        c.1,3/2,+-5
b.1,3/2,+-5i                         d.-1,-3/2,+-5

anonymous · Answer

c

anonymous · Answer

if youre given the answers like that, the easiest way to solve it is to plug in the numbers for x to see if they give you 0

anonymous · Answer

Ok thanks bro. I really have a hard time with math.

anonymous · Answer

just take the easy way out and youll be fine haha

mathmate · Answer

Descartes rule of signs indicates that there are 0,2 or 4 positive roots.
Choice C has 3 positive roots, so there is a problem.
The best way to find out is to either substitute the values.
f(5)=1400, f(5i)=0, so b would be the more appropriate answer.