If the scores on previous tests were 84, 85, 87, and 99, what is needed on the next test to have a 90 average exactly?

If the discriminant if a quadratic equation is 4 which statement describes the roots?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?

Write the factored form of this trinomial 9x^2+18x-7