Answer:
Step-by-step explanation:
f(x)=2x³+5x²-8x-2
+ + - -
there is only one change of sign.
Hence it has only one positive rational root.
f(-x)=-2x³+2x^2+8x-2
- + + -
it has two negative rational roots.
or two negative irrational roots.
∵irrational roots always occur in pairs.
possible rational roots are 1 or 3
