In solving simultaneous equations, this question shows you the best scenario you can hope for.
Two of the variables are additive inverses which means that if you add the two equations together, the y-terms will add to give 0 and are thus eliminated
#color(white)(xxxxxxxxxx) +5x color(red)(+ 3y) = +13#..........................A
#color(white)(xxxxxxxxxx)- 6x color(red)(- 3y) = - 15#...........................B
#A+B:color(white)(xxxxx) -x " " = -2" "larr# only x!
#color(white)(xxxxxxxxxxxx) x " " = +2#
Substitute 2 for #x# in equation A
#color(white)(xxxxxxxxxx) +5(2) + 3y = +13#
#color(white)(xxxxxxxxxx) +10" + "3y = +13#
#color(white)(xxxxxxxxxxxxxxxxx)3y = +13-10#
#color(white)(xxxxxxxxxxxxxxxxx)3y = 3#
#color(white)(xxxxxxxxxxxxxxxxxx)y = 1#
#x = 2 and y = 1#
