Find the value of `x+y`, if `5x-2y=4` and `x+8y=26`.

Find the value of x-y , if 5x+4y=14 and 4x+5y=13 .

Find the value of x if y=(3)/(4)x and 5x+8y=33.

Find the value of (x+y),if 5x-2y=10,x+8y=26

Find the value of (x-y), if 2x-5y=5,5x-8y=14

Find the value of (x-y) , if 5x+4y=14,4x+5y=13

Find the value of 27 x^3+\ 8y^3, if (i) 3x+2y=14 and x y=8 (ii) 3x+2y=20\ and x y=(14)/9

(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.

If x : y = 4 : 7 , find the value of (3x + 2y) : (5x + y) .

Find the value of x^3-8y^3-36 x y-216 , when x=2y+6.