Find the value of y :

`4/7 times ( y + 7 ) = 4`

Find the value of : 7^4

Find the value of   3 4/7 ÷ 7

Find the value of : ( 5/8)^-7 times (8/5)^-4

Find the value of : ( x / y )^x times ( y/x )^y , x = 4 , y = -7

Find the value of [ (1/4 )^2 times ( 1/7 )^2 ] ÷ [ (1/7)^6 ÷ ( 1/7 )^1 ]

Find the value of x and y if: (a) (x-4, 7) = (4,7)

Find the value of ( (x^-2 times y^-4 )/ ( x^-3 times y^-1) ÷ y^-2/x^-1 )

Find the value of y when (5y-7)/(3y)=2

Find the values of (x-y) , if (i) 3x + 4y = 11 , 4x + 3y = 10 (ii) 3x + 2y = 8 , 2x + 3y = 7

For solving the following sikmultaneous equations by Cramer's rule, find the values of D_x and D_y : 3x - y = 7, x + 4y = 11