Evaluate the integral using any appropriate algebraic method or trigonometric identity.

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{7-98x}{\sqrt[\phantom{2}]{81-49x^2}}dx$

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{7-98x}{\sqrt[\phantom{2}]{81-49x^2}}dx=$