First slide

Pair of straight lines

Question

If $x^{2} + 4 x y + y^{2} = 0$ represents two sides of $Δ O A B$ and the orthocentre is (-1, -1), then the third side is

Moderate

A

$x + y = 2$
B

$x + y = 1$
C

$x + y + 1 = 0$
D

$x + y = 3$

Solution

$\begin{array}{l} a = 1, 2 h = 4, b = 1 \\ (l, m) = (- 1, - 1) \end{array}$
$(a + b) (l x + m y) = a m^{2} - 2 h l m + b l^{2}$
$\Rightarrow x + y = 1$

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