Which is true regarding chords and diameters of circles?

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Luigi is the first person to finish a 5k race and is standing 13 feet beyond the finish line. another runner, mario, is still running the race and has approximately 24 feet before he reaches the finish line. what is the distance between mario and luigi? explain through words, numbers or pictures how you found the answer.

Anutrition company is marketing a low calorie snack brownie. a serving size of the snack is 3 brownies and has a total of 50 calories. determine how many calories 21 brownies would have