= 9n + 63
generate the first few terms using the recursive equation
f(1) = 72
f(2) = 72 + 9 = 81
f(3) = 81 + 9 = 90
f(4) = 90 + 9 = 99
the sequence is 72, 81, 90, 99, .....
This is an arithmetic sequence whose n th term formula is
=
+ (n - 1 )d
where is the first term and d the common difference
d = 99 - 90 = 90 - 81 = 81 - 72 = 9 and = 72
= 72 + 9(n - 1) = 72 + 9n - 9 = 9n + 63 ← explicit formula
Answer:
Solution : (15, - 11)
Step-by-step explanation:
We want to solve this problem using a matrix, so it would be wise to apply Gaussian elimination. Doing so we can start by writing out the matrix of the coefficients, and the solutions ( - 5 and - 2 ) --- ( 1 )
Now let's begin by canceling the leading coefficient in each row, reaching row echelon form, as we desire --- ( 2 )
Row Echelon Form :
Step # 1 : Swap the first and second matrix rows,
Step # 2 : Cancel leading coefficient in row 2 through ,
Now we can continue canceling the leading coefficient in each row, and finally reach the following matrix.
As you can see our solution is x = 15, y = - 11 or (15, - 11).