Question

Possible rational roots for 2x^3+5^2-8x-2=0

Answer 1

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