Solving for portfolio weights

I am having trouble solving the following equation without using trial and error example - 10.2 = 9w + 12.25(1-W). I get all the concepts but am spending way too much time trying to solve to two decimal places. Any help here is appreciated - I know the answer is fairly basic algerbra but excel and goal seek has made me a bit dumb.

10.2 = 9w + 12.25(1 − w)

10.2 = 9w + 12.25 – 12.25w

3.25w = 2.05

w = 2.05 / 3.25 = 0.6308

1 – w = 0.3692

63.08% of the security that returns 9%, 36.92% of the security that returns 12.25%.

Another approach is to look at what percentage of the way from 9 to 12.25 gets us to 10.2:

(10.2 – 9) / (12.25 – 9) = 0.3692.

thanks, perfect response

My pleasure.