Given, y = 4x - 7    .......1

and 16x - 5y = 25  .......2

Put value of y from equation 1 in equation 2, we get'

     16x - 5(4x - 7) = 25

=> 16x - 20x + 35 = 25

=> -4x = 25 - 35

=> -4x = -10

=> 4x = 10

=> x = 10/4

=> x = 5/2

Put value of x in equation 1, we get

     y = 4(5/2) - 7

=> y = 2 * 5 - 7

=> y = 10 - 7

=> y = 3

Hence, x = 5/2, y = 3