First slide

Equation of line in Straight lines

Question

If the line passing through $(3, 4)$ and $(x, 5)$ makes $135 °$ angle with the positive direction of $x -$ axis, then $x =$

Easy

A

$- 2$
B

$2$
C

$- 1$
D

1

Solution

Since the line passing through $(3, 4)$ and $(x, 5)$ makes an angle of $135 °$ with $x -$ axis. Therefore, its slope is $\tan 135 ° = - 1 .$ But, the slope of the line is also equal to
$\frac{5 - 4}{x - 3}$ $[Using : m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}]$
$∴ - 1 = \frac{5 - 4}{x - 3} \Rightarrow - x + 3 = 1 \Rightarrow x = 2 .$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App