Resposta:
Mirar abaix:
Explicació:
Si
# 4x-5y = -1 # (anomenem "1")
i
# 2x + y = 5 #
llavors
# 4x + 2y = 10 # (anomenem "2")
(Restar 2 de 1)
# -7y = -11 #
# y = 11/7 #
Per tant:
# 2x + (11/7) = 5 #
# 2x = (35/7) - (11/7) #
# 2x = (24/7) #
# x = (24/7) / 2 #
# x = (24/14) #
# x = (12/7) #