Question

Two points have coordinates $a(1,2)\text{and}b(x,4)$. If the line joining them has $\text{slope}=1$, the value of $x$ is

• A. $4$
• B. $-3$
• C. $3$
• D. $-5$

Answer 1

The correct option is C $3$

We know that, slope of a line is given by
$m=\frac{y_2-y_1}{x_2-x_1}$.
Given, $\text{slope}=1$
$\therefore m=\frac{y_2-y_1}{x_2-x_1}=1$
$\Rightarrow m=\frac{4-2}{x-1}=1$
$\Rightarrow \frac{4-2}{x-1}=1$
$\Rightarrow x-1=4-2=2$
$\Rightarrow x=2+1=3$