At last! Posted another problem after 5 weeks

Algebra Level 3

If $r_{1}, r_{2}, r_{3}, r_{4}$ are the roots of the equation $4x^{4}-3x^{3}-x^{2}+2x-6=0$ , what is the value of $\frac{1}{r_{1}}+\frac{1}{r_{2}}+\frac{1}{r_{3}}+\frac{1}{r_4}$ ?