First, solve the second equation for #y#:
#16x - 5y - 16x = 50 - 16x#
#-5y = 50 - 16x#
#(-5y)/-5 = (50 - 16x)/-5#
#y = 50/-5 - (16x)/-5#
#y = -10 + (16/5)x#
Next, substitute #-10 + (16/5)x# for #y# in the first equation and solve for #x#:
#8x + 3(-10 + (16/5)x) = 58#
#8x - 30 + (48/5)x = 58#
#8x - 30 + (48/5)x + 30 = 58 + 30#
#8x + (48/5)x = 88#
#(5/5)8x + (48/5)x = 88#
#(40/5)x + (48/5)x = 88#
#88/5x = 88#
#5/88 88/5x = 88 5/88#
#x = 5#
Finally, substitute #5# for #x# in the solution for the second equation and solve for #y#:
#y = -10 + (16/5)5#
#y = -10 + 16#
#y = 6#