2 x^4 + x^2 - 22 x + 8 = 0
possible rational roots = + or - of factors of 8 / + or - of factors of 2 =
One root by checking = 2
zero or root cannot be negative. LHS will be positive for -ve x.
Just by looking at the coefficients: maximum possible 8/2 and minimum possible 1/2
F(x) = A (x - C1)(x - C2) (x - C3) (x - C4) polynomial of degree 4.
Multiply and form the polynomial. In that, we will have the
Leading Coeffient of x^4 : A
constant term : coefficient of x^0 : A C1 C2 C3 C4
So the possible rational zeros can be obtained by :
+ or - of factors of constant term / leading coefficient
Our case : rational zero's are possibly : +- factors of 8 / factors of 2
: 8/2 , -8/2, +- 1, +-2 , +- 1/2