₹ 80 = x notes of ₹ 20 ₹ 80 = y notes of ₹ 5 ₹ 80 = z notes of ₹ 2 Which of the following are the values of x, y and z?
Find the value of 4x2+y2+25z2+4xy−10yz−20zx when x = 4, y = 3 and z = 2.