Multiply each side of the equation by #color(red)(5)/color(blue)(3)# to solve for #a# while keeping the equation balanced:
#color(red)(5)/color(blue)(3) xx -6 = color(red)(5)/color(blue)(3) xx 3/5a#
#-30/color(blue)(3) = cancel(color(red)(5))/cancel(color(blue)(3)) xx color(blue)(cancel(color(black)(3)))/color(red)(cancel(color(black)(5)))a#
#-10 = a#
#a = -10#
To check the solution substitute #color(red)(-10)# for #color(red)(a)# in the original equation and calculate the result on the right side of the equation to ensure it equals #-6#
#-6 = 3/5color(red)(a)# becomes:
#-6 = 3/5 xx color(red)(-10)#
#-6 = 3/color(red)(cancel(color(black)(5))) xx cancel(color(red)(-10))-2#
#-6 = 3 xx -2#
#-6 = -6#
Therefore the solution is correct.
