Com es resol el sistema lineal següent ?: 3x - 2y = 7, 11x + 3y + 7 = 0?

# 3x-2y = 7 ………. (i) #

# 11x + 3y + 7 = 0 implica 11x + 3y = -7 ………… (ii) #

Multiplica # (i) # per #3# i (ii) per 2 i afegir

# implies9x-6y = 21 #

# 22x + 6y = -14 #

A més, tenim

# 31x + 0 = 7 #

#implies x = 7/31 #

Posa # x = 7/31 # in # (i) #

#implies 3 (7/31) -2y = 7 #

#implies 21 / 31-2y = 7 #

#implies 2y = 21 / 31-7 #

#implies 2y = (21-217) / 31 #

#implies 2y = -196 / 31 #

#implies y = -98 / 31 #