# 7x + y = -2 ……………….. (i) #
# -7x + y = -9 …………………… (ii) #
Pridať (i) a (ii)
#implies 2y = -11 #
#implies y = -11 / 2 #
dať # Y = -11 / 2 # v # (I) #
#implies 7x-11/2 = -2 # znásobiť obe strany #2#
# Implies14x-11 = -4 #
#implies 14x = 7 #
#implies x = 1/2 #
