Question

x + y = 3 ; x - y = 1
What is the solution (x , y) of the above system of equations ?

• A. (2 , 1)
• B. (-2 , -1)
• C. (3, -4)
• D. (-3, -4 )

Answer 1

The correct option is A (2 , 1)

x + y = 3 .....(i)
x - y = 1 .....(ii)
We use elimination method to solve the above equations. It is evident that if we add the two equations, we can eliminate the variable y.
x + y = 3
x - y = 1
_________
2x = 4
or x = 2
Substitute the value of x in equation (i)
2 + y = 3
Subtract 2 from both sides to get y = 1
Therefore the solution is (2 , 1)