Answer:
-0.8 and 0.75.
Step-by-step explanation:
20x^4 + x^3 + 8x^2 + x – 12 = 0
by the rational roots theorem:-
The leading coefficient is 20 with factors +/- 1,2,4,5,10,20
and the constant is -12 with factors +/- 1,2,3,4,6,12
so there are many possible roots like -1, 2, 3/4 3/5 , -4/5 .....
Drawing a graph would be the quickest way to do this, either manually, using graphical software or a graphical calculator.
I used the latter and got 2 rational roots -0.8 and 0.75.