X = (12 +- sqrt (144 -4(7)(3))/14
x = (12 + - sqrt (144 - 84))/14
x = (12 + - sqrt(60))/14
x = (12 + - 2sqrt 15))/14
x = (6 + - sqrt 15) / 7
I can help you with #20. For example, lets say 3/5, this fraction would be made up of 5 parts and 3 are covered, which doesn't make it full, if it was 5/5 it would be full. When you do something with a reciprocal you turn it over, so 3/5 would be turned over to 5/3, thus making it a whole number