\(\text{I think I'd just use the quadratic formula and see what comes out }\\ r_{1,2} = \dfrac{19 \pm \sqrt{19^2 + 4\cdot 63\cdot 30}}{126} = \dfrac{19\pm 89}{126} \\ r_{1,2} = \dfrac 6 7,~-\dfrac{5}{9} \)
\(\text{so }63x^2-19x-30 = \\ 63 \left(x - \dfrac 6 7\right)\left(x + \dfrac 5 9\right) = \\ (7x-6)(9x+5)\)
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