This is a quadratic equation. To find n we multiply the last terms in each bracket together (2 times -5) = -10

To find ?a? we multiply the first terms in each bracket together (3x times 2x) = 6x2, So a = 6.

Thus a - n = 16

To find k we multiply the first term in the first bracket by the second term in the second bracket and add the result to the product of the second term in the first bracket and the first term in the second. (-15x + 4x) = -11x. So k = -11

16 - 11 = 5

Let number of hit shots be 'X'
Let number of miss shots be 'Y'
Given X + Y = 40....(1)
50X - 10Y = 500.....(2)
Solving 1 and 2, we get
X = 15 and Y = 25
Therefore, number of hits = 15

Any two digit number can be written as (10P + Q), where P is the digit in the tens place and Q is the digit in the units place.
P + Q = 8 ----- (1)
(10Q + P) - (10P + Q) = 54
9(Q - P) = 54
(Q - P) = 6 ----- (2)
Solve (1) and (2) P = 1 and Q = 7
The required number is = 17