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the midpoint of a segment can be found using the formulas for a directed line segment, x = (x2 – x1) + x1 and y = (y2 – y1) + y1. when using these formulas to find a midpoint, which is true?

a. a = 1 and b = 2
b. a = 2 and b = 1
c. a = 1 and a + b = 2
d. a = 2 and a + b = 2

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

Set up and solve a proportion for the following application problem. if 55 pounds of grass seed cover 404 square feet, how many pounds are needed for 7272 square feet?

Which expression is the factorization of x^2+10+21