Browse Questions

# Fill in the bank for the following : the line which cuts off equal intercept from the axes and pass through the point (1, -2) is _________.

$\begin {array} {1 1} (A)\;x+y-1=0 & \quad (B)\;x-y+1=0 \\ (C)\;x-y-1=0 & \quad (D)\;x+y+1=0 \end {array}$

Toolbox:
• Equation of a line in its intercept form is $\large\frac{x}{a}$$+ \large\frac{y}{b}$$=1$ where $a$ and $b$ are the intercepts on the coordinate axes.
Step 1 :
Given $a = b$
Hence the equation of the line is $\large\frac{x}{a} $$+\large\frac{y}{a}$$=1$
$\Rightarrow x+y=a$
It passes through the point (1, -2)
$\therefore 1-2=a$
$\Rightarrow a = -1$
Hence equation of the line is $\large\frac{x}{-1}$$+\large\frac{y}{-1}$$=1$
$\Rightarrow x+y=-1$ or $x+y+1=0$
Hence the equation of the required line is $x+y+1=0$