Los het systeem op: x + y = 4, 2x-y = 5?

Antwoord:

y = 1

x = 3

Uitleg:

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

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

Vanaf 1),

# X + y = 4 #

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

Sub (3) in (2)

# 2x-y = 5 #

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

# 8-2y-y = 5 #

# 8-3y = 5 #

# 3 = 3 j #

# Y = 1 # --- (4)

Sub (4) in (3)

# X = 4-y #

# X = 4-1 #

# X = 3 #