As we know with any math problem, brackets always need to be sorted out first using BIDMAS. So first, we would expand the brackets.
#color(red)(-3)color(green)((t+color(red)(5))+color(green)((4t+color(red)(2))=color(red)(8)#
#color(red)(-3 xx color(green)(t)=color(green)(3t)#
#color(red)(-3 xx 5)=color(red)(-15#
As #color(green)((4tcolor(red)(+2))# cannot be expanded by anything is stays the same.
Removing the brackets:
#color(green)(-3t)color(red)(-15)+color(green)(4t)color(red)(+2)=color(red)(8)#
Collecting like-terms:
#color(green)(-3t+4t=t)#
#color(red)(-15+2=-13#
Plugging back into equation:
#color(green)(t)color(red)(-13)=color(red)(8)#
To get #color(green)(t)# on it's own, we #color(red)(+13)# to get rid of the #color(red)(-13)# as they cancel out. Remember we add #color(red)(13)# to both sides.
#color(red)(8+13=21)#
#therefore# #t=21#
