First, you expand the term in parenthesis by multiplying each individual term within the parenthesis by #color(red)(-1.3)#:
#color(red)(-1.3)a + (color(red)(-1.3) * -6) = -2.6#
#-1.3a + 7.8 = -2.6#
Next, we can substract #color(blue)(7.8)# from each side of the equation to isolate the #a# term and keep the equation balanced:
#-1.3a + 7.8 - color(blue)(7.8) = -2.6 - color(blue)(7.8)#
#-1.3a + 0 = -10.4#
#-1.3a = -10.4#
Now, we can divide each side of the equation by #color(green)(-1.3)# to solve for #a# and keep the equation balanced:
#(-1.3a)/color(green)(-1.3) = (-10.4)/color(green)(-1.3)#
#(color(green)(cancel(color(black)(-1.3)))a)/cancel(color(green)(-1.3)) = 8#
#a = 8#
