Question

Select the correct approach for solving a pair of linear equations in 2 variables by elimination method.
i) Add or subtract one equation from the other so that one variable gets eliminated.
ii) Multiply both the equations by any non-zero constant to make the coefficients of one variable (either x or y) numerically equal.
iii) Solve the equation in one variable (x or y) to get its value.
iv) Substitute the value of x (or y) in either of the original equations to get the value of the other variable.

• A. (ii), (i), (iv), (iii)
• B. (i), (ii), (iii), (iv)
• C. (i), (iv), (ii), (iii)
• D. (ii), (i), (iii), (iv)

Answer 1

The correct option is D

(ii), (i), (iii), (iv)

Let there be two equations.
x + y = 3....(1) and 2x + y = 4.....(2)

1st step:
Multiply equation (1) by 2 to make coefficient of x same in both the given equations.
On multiplying, equation (1) becomes 2x + 2y = 6....(3).

2nd step:
Subtracting equation (2) by equation (3) i.e.
(2x + 2y = 6) - (2x + y = 4)
we get
$y=2$.

3rd step:
On solving, we get y = 2.

4th step:
On putting the value y = 2 in the equation (1),
we get x = 1.