Solve for x in the equation x^2 - 8x + 40 = 0​

Galen sold tickets of his church’s carnival for a total of $2,820. children’s tickets cost $3 each and adult tickets cost $5 each. the number of children’s tickets sold was 30 more than 3 times the number of adult tickets slod. how many children’s ticket and how many adult tickets did he sell?

In the diagram below? p is circumscribed about quadrilateral abcd. what is the value of x

I’m still confused on how to work the percentages