#color(red)("To find x and y, you need to solve these equations simultaneously:")#
#y=-2x-17# #.........(1)#
#-x+11y=66# #.........(2)#
sub #(1)# into #(2)#:
#-x+11(-2x-17)=66#
#color(red)("Expand the brackets:")#
#-x-22x-187=66#
#color(red)("Group like terms:")#
#-23x-187=66#
#color(red)("Put all integers on the right:")#
#-23x=253#
#color(red)("Isolate x:")#
#therefore x=-11#
#color(red)("Now to find y:")#
sub #x=-11# into #(1)#:
#y=-2(-11)-17#
#color(red)("Expand brackets and simplify:")#
#y=22-17#
#therefore y=5#
#color(red)("Putting what we have found all together:")#
#therefore x=-11,# #y=5#