Question

The point (1,2) lies on the line _____.

• A. x + 2y = 5
• B. 2x + y = 5
• C. 4x – y = 5
• D. 3x – 2y = 1

Answer 1

The correct option is A

x + 2y = 5

A point lies on a line if its coordinates satisfy the equation of the line.

Substituting $(1,2)$ in the equation,

1) $x+2y=5\Rightarrow 1+2\left(2\right)=5,\text{satisfies the equation}$

2) $2x+y=5\Rightarrow 2\left(1\right)+2=4\ne 5,\text{does not satisfy the equation}$

3) $4x–y=5\Rightarrow 4\left(1\right)–2=2\ne 5,\text{does not satisfy the equation}$

4) $3x–2y=1\Rightarrow 3\left(1\right)–2\left(2\right)=-1\ne 1,\text{does not satisfy the equation}$

$\therefore$ (1,2) lies on the line $x+2y=5$