Question

Find out which of the following equations have x=1, y=2 as solution.
x + 2y = 5
2y - 3x + 3 = 0
3x + 4y - 8 = 0 [4 MARKS]

Answer 1

Concept and result : 1 Mark
Equation calculation : 1 Mark each

Putting x = 1, y = 2 in the equation x + 2y = 5,

1 + (2x2) = 5

The equation holds. Hence x = 1, y = 2 is a solution of the equation x + 2y = 5

Putting x = 1, y = 2 in the equation 2y – 3x + 3 =0,

$(2\times 2)–(3\times 1)+3=4\ne 0$

The equation does not hold. Hence x = 1, y = 2 is not a solution of the equation 2y – 3x + 3 =0

Putting x = 1, y = 2 in the equation 3x + 4y – 8 =0,

$(3\times 1)+(4\times 2)-8=3\ne 0$

The equation does not hold. Hence x = 1, y = 2 is not a solution of the equation 3x + 4y – 8 =0