SOLVE FOR "N"? INTERMEDIATE MATH

CAN YOU SOLVE FOR N (so that the expression is a perfect square tri.) AND FACTOR ?? please and thankyou.

1) c^(2)+6c+n

2) x^(2)-18x+n

3) x^(2)-7x+n

5) c^(2)-2/5c+n

6) x^(2)+2/5x+n

1) c^(2)+6c+n

take 1/2 of 6 to get 3. square this and get n = 9
c^2 + 6c + 9 = (c+3)^2

2) x^(2)-18x+n

take 1/2 of -18 to get -9. square this and get n = 81
x^2 -18x +81 = (x - 9)^2

3) x^(2)-7x+n

take 1/2 of -7 to get -7/2. square this and get n = 49/4
x^2 - 7x + 49/4 = (x - 7/2)^2

5) c^(2)-2/5c+n

take 1/2 of -2/5 to get -1/5. square this and get n = 1/25
c^2 - (2/5)c + 1/25 = (x - 1/5)^2

6) x^(2)+2/5x+n

take 1/2 of 2/5 to get 1/5. square this and get n = 1/25
x^2 + (2/5)x + 1/25 = (x + 1/5)^2