Find the equation of the straight line which passes through the point (1, – 2) and cuts off equal intercepts from axes

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

Toolbox:
• Equation of a line which has $a$ and $b$ as the $x$ and $y$ intercepts is $\large\frac{x}{a}$$+\large\frac{y}{b}$$=1$
Step 1
It is given that the straight line cuts of equal intercepts.
$\therefore \large\frac{x}{a}$$+\large\frac{y}{b}$$=1$
$\Rightarrow x+y=a$
It is also given that the line passes through the point (1, -2)
$\therefore 1+(-2)=a$
$\Rightarrow a = -1$
Hence the eqution of the line is
$x+y=-1$ or
$x+y+1=0$