Practice30 Create account

For what value of $k$ will the pair $x + 2 y = 3$ and $3 x + k y = 9$ have its two graphs coincide (infinitely many solutions)?

Class 10Graphical MethodAlgebra — Systems of Equations

A6
B7
C5
D12

Step-by-Step Solution

For coincident lines

\frac{a _{1}}{a _{2}} = \frac{b _{1}}{b _{2}} = \frac{c _{1}}{c _{2}} : \frac{1}{3} = \frac{2}{k} = \frac{3}{9}

. From

\frac{1}{3} = \frac{2}{k}, k = 6

. Check

\frac{3}{9} = \frac{1}{3}

. So

k = 6

.

Answer: A) 6

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Graphical Method practice questions

More Class 10 Graphical Method practice

For what value of p will the graphs of 2x + 3y = 5 and 4x + py = 7 be parallel (no…Three lines are graphed: x + y = 6, x - y = 2, and y = 1. The first two meet at (4, 2).…A garden has the boundary line x + y = 10 (in metres). A path is drawn as the line y =…The graph of a linear equation in two variables is always a:The point where the graphs of two linear equations intersect gives: