Find the roots of the quadratic function x^2=100

The ratio of blue cards to green cards is 2 to 5. there are 8 blue cards. complete the diagram and explain how you can find the number of green cards.

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?