Step 1) Because the first equation is already solved for #x#, substitute #-10 + y# for #x# in the second equation and solve for #y#:
#-6x + 8y = 22# becomes:
#-6(-10 + y) + 8y = 22#
#60 - 6y + 8y = 22#
#60 + 2y = 22#
#60 + 2y - color(red)(60) = 22 - color(red)(60)#
#60 - color(red)(60) + 2y = -38#
#0 + 2y = -38#
#2y = -38#
#(2y)/color(red)(2) = -38/color(red)(2)#
#(color(red)(cancel(color(black)(2)))y)/cancel(color(red)(2)) = -19#
#y = -19#
Step 2) Substitute #-19# for #y# in the first equation and calculate #x#:
#x = -10 + y# becomes:
#x = -10 + -19#
#x = -29#
The solution is: #x = -29# and #y = -19# or (-29, -19)