Find the equation of the line passing through the point
Find the equation of the line passing through the point (2, 2) and cutting off intercepts on the axes, whose sum is 9.
To Find: The equation of the line passing through the point (2, 2) and cutting off intercepts on the axes, whose sum is 9.
Given : Let $\mathrm{a}$ and $\mathrm{b}$ be two intercepts of $\mathrm{x}$-axis and $\mathrm{y}$-axis respectively.
sum of the intercepts is $9, i . e, a+b=9$
$\Rightarrow a=9-b$ or $b=9-a$
Formula used:
The equation of a line is given by:
$\frac{x}{a}+\frac{y}{b}=1$
The given point (2, 2) passing through the line and satisfies the equation of the line.
$\frac{2}{a}+\frac{2}{9-a}=1$
$2(9-a)+2 a=9 a-a^{2}$
$18-2 a+2 a=9 a-a^{2}$
$a^{2}-9 a+18=0$
$a^{2}-6 a-3 a+18=0$
$a(a-6)-3(a-6)=0$
$(a-3)(a-6)=0$
$a=3, a=6$
when $a=3, b=6$ and $a=6, b=3$
case $1:$ when $a=3$ and $b=6$
Equation of the line : $\frac{\mathrm{x}}{\mathrm{a}}+\frac{\mathrm{y}}{\mathrm{b}}=1$
$\frac{x}{3}+\frac{y}{6}$
Hence, 2x + y = 6 is the required equation of the line.
case 2 : when a=6 and b=3
Equation of the line : $\frac{\mathrm{x}}{\mathrm{a}}+\frac{\mathrm{y}}{\mathrm{b}}=1$
$\frac{x}{6}+\frac{y}{3}=1$
Hence , x + 2y = 6 is the required equation of the line.
Therefore, $2 x+y=6$ is the required equation of the line when $a=3$ and $b=6$.And, $x+2 y$ $=6$ is the required equation of the line when $a=6$ and $b=3$.