[tex]\boxed{\boxed{\pink{\bf \leadsto The \ slope \ of \ the \ line \ is \ \dfrac{-25}{21}.}}}[/tex]
Two points are given to us and we need to find the slope of the line . The slope of the line passing through points [tex]\bf (x_1,y_1 ) \ \& \ (x_2,y_2) [/tex] is given by ,
[tex]\qquad\boxed{\red{\bf Slope = tan\theta=\dfrac{y_2-y_1}{x_2-x_1}}}[/tex]
Here , the points are ,
[tex]\bf\implies Slope = \dfrac{y_2-y_1}{x_2-x_1} \\\\\bf\implies Slope =\dfrac{15-(-10)}{-15-6} \\\\\bf\implies Slope = \dfrac{15+10}{-21}\\\\\bf\implies Slope =\dfrac{-1(25)}{-1(-21)}\\\\ \bf\implies\boxed{\red{\bf Slope =\dfrac{-25}{21}}}[/tex]