Trouble finding the interest rate with large numbers? Help

When I plug it into the quadratic equation, I get a weird answer that doesn't make sense. Help me please I can't figure this out. I've tried it a couple of ways, but I'm stuck...ideas? Help me please..

Using: A=P1(1+r)^2 + P2(1+r)

Business invests 10,000 in a savings account for 2 yr. At the beginning of the second year, an additional 3500 is invested. If a total of 14,822.75 is in the account at the end of the second year, what is the annual interest rate?

14822.75 = 10000(1 + r)^2 + 3500(1 + r)
14822.75 = 10000(1 + 2r + r^2) + 3500 + 3500r
14822.75 = 10000 + 20000r + 10000r^2 + 3500 + 3500r
14822.75 = 10000r^2 + 23500r + 13500
0 = 10000r^2 + 23500r - 1322.75

solve quadratically

(-23500 ± √605160000) / 20000
(-23500 ± 24600) / 20000
ignore negative solution

.055

5.5%

10000(1 + .055)^2 + 3500(1 + .055)
10000 * 1.113025 + 3500 * 1.055
11130.25 + 3692.5
14822.75

10,000 (1 + r)^2 + 3500 (1 + r) = 14822.75
10,000 (1 + r)^2 + 3500 (1 + r) - 14822.75 = 0

this is a quadratic in terms of 1 + r

so a = 10,000 , b = 3500, and c = -14822.75

(1 + r) = [-3500 +/- sqrt(3500^2 - 4(10,000)(-14822.75))] / (2 * 10000)
(1 + r) = [-3500 +/- sqrt(12250000 - 592910000)] / 20000
(1 + r) = [-3500 +/- sqrt(580660000)] / 20000
(1 + r) = [-3500 +/- 24097] / 20000

taking the positive root:
(1 + r) = [-3500 + 24097] / 20000 = 1.0298

thus, r = .0298 = 2.98%

the annual percentage yield is 2.98% (assuming annual compounding)

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