SOLUTION: can you explain to me how can i solve this 18z + 45 + z2

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Question 623213: can you explain to me
how can i solve this
18z + 45 + z2

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
18z + 45 + z^2 \Note use of ^ (uppercase 6)
If You meant:
f(z) = z%5E2+%2B+18z+%2B+45 and to find where f(z) = 0
z%5E2+%2B+18z+%2B+45 = 0
Quadratic formula ALWAYS works
z+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
z+=+%28-18+%2B-+sqrt%28+18%5E2-4%2A1%2A45+%29%29%2F%282%29+
z+=+%28-18+%2B-+sqrt%28144%29%29%2F%282%29+
z+=+%28-18+%2B-+12%29%2F%282%29+
z = -3 and z = -15
OR by factoring:
z%5E2+%2B+18z+%2B+45 = 0
(z + 3)(z+15) = 0