Find the value of $(x+y)$ and $(x-y)$, if
$\left(i\right)$ $15x-17y=11$ , $17x-15y=21$.
$\left(ii\right)$ $12x+13y=29$, 13x+12y=21.

Find the value of $x-y$, if $3x+4y=11$ and $4x+3y=12$.

Find the value of $x+y$, if
$12x+13y=29$ and
$13x+12y=21$

Find the value of x and y I. $18x^2-9x+1=0$
II. $12y^2-y-1=0$

Find the value of x and y in the given equation $5\frac{7}{x}\times y\frac{1}{13}=12$:

IF 12x=0.3y then value of $\frac{y-x}{y+x}$ will be

If $x=3\text{and}y=4$, find the value of
(i) $3x+2y$
(ii) $4x+3y$
(iii) $18xy$
(iv) $\frac{15x}{12y}$

Solve for x,y. $x^2+y(x+1)=17$ and $y^2+x(y+1)=13$

(i)$7x^2+16x-15=0$
(ii) $5y^2+8y-21=0$

The value of k for which the lines $5x+7y=3$ and $15x+21y=k$ coincide is

(i) x+2y=-7 and 3x-2y=-1, then find the value of x.
(ii) If x+y=8 and 4y-x=2, then find the value of y.
(iii) If 3x+5y=9 and 5x+3y=7, then find the value of x+y.
(iv) If 3x-y=11 and x-3y=17, then find the value of x-y.