Answer:
X + Y = 1 ------1
X - 2y = 4 ------2
Solving by substitution method
X = 4 + 2y -----3
Putting the value of X in equation 1
4 + 2y + y = 1
4 + 3y = 1
3y = 1 - 4
3y = (-3)
y = (-3) /3
y = (-1)
Putting value of y in equation 3
X = 4 + 2(-1)
X = 4 - 2
X = 2
