Find the value of k for which each of the following system of equations have infinitely many solutions :
Find the value of k for which each of the following system of equations have infinitely many solutions :
$2 x+3 y=7$
$(k+1) x+(2 k-1) y=4 k+1$
GIVEN:
$2 x+3 y=7$
$(k+1) x+(2 k-1) y=4 k+1$
To find: To determine for what value of k the system of equation has infinitely many solutions
We know that the system of equations
$a_{1} x+b_{1} y=c_{1}$
$a_{2} x+b_{2} y=c_{2}$
For infinitely many solution
$\frac{a_{1}}{a_{2}}=\frac{b_{1}}{b_{2}}=\frac{c_{1}}{c_{2}}$
Here
$\frac{2}{(k+1)}=\frac{3}{2(k-1)}=\frac{7}{4 k+1}$
$\frac{2}{(k+1)}=\frac{3}{2(k-1)}$
$2 \times(2 k-1)=3(k+1)$
$4 k-2=3 k+3$
$4 k-3 k=2+3$
$k=5$
Now again consider the following to find k
$\frac{3}{2(k-1)}=\frac{7}{4 k+1}$
$3(4 k+1)=7 \times 2(k-1)$
$12 k+3=14 k-14$
$14+3=14 k-12 k$
$k=5$
Hence for $k=5$ the system of equation have infinitely many solutions