Vyriešte systém: x + y = 4, 2x-y = 5?

Vyriešte systém: x + y = 4, 2x-y = 5?
Anonim

odpoveď:

y = 1

x = 3

vysvetlenie:

# X + y = 4 # --- (1)

# 2x-y = 5 # --- (2)

Od (1),

# X + y = 4 #

# X = 4-y # --- (3)

Sub (3) až (2)

# 2x-y = 5 #

# 2 (4-y) -y = 5 #

# 8-2y-y = 5 #

# 8-3y = 5 #

# 3 = 3r #

# Y = 1 # --- (4)

Sub (4) do (3)

# X = 4-y #

# X = 4-1 #

# X = 3 #