Answer:
1.20, 10.8
Explanation:
d = n^2 - 12n + 43
d = 30
30 = n^2 - 12n + 43
0 = n^2 - 12n + 13
now solve for n using quadratic formula:
a=1, b=-12, c=13
n = (-b +- sqrt( b^2 -4ac))/2a
two answers ( one for + the square root, one for - the square root)
n = 1.20, n = 10.8