Step 1: Because the second equation is already solved for #y# we can substitute #(-4x + 19)# for #y# in the first equation and solve for #x#:
#-x - 2y = -17# becomes:
#-x - 2(-4x + 19) = -17#
#-x - (2 xx -4x) - (2 xx 19) = -17#
#-x - (-8x) - 38 = -17#
#-1x + 8x - 38 = -17#
#(-1 + 8)x - 38 = -17#
#7x - 38 = -17#
#7x - 38 + color(red)(38) = -17 + color(red)(38)#
#7x - 0 = 21#
#7x = 21#
#(7x)/color(red)(7) = 21/color(red)(7)#
#(color(red)(cancel(color(black)(7)))x)/cancel(color(red)(7)) = 3#
#x = 3#
Step 2: Substitute #3# for #x# in the second equation and calculate #y#:
#y = -4x + 19# becomes:
#y = (-4 xx 3) + 19#
#y = -12 + 19#
#y = 7#
The Solution Is: #x = 3# and #y = 7# or #(3, 7)#
