What is the value of y in the solution to the system of equations?
x + y = 1
2x – 3y = –30

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180

Type the correct answer in each box. use numerals instead of words. if necessary, use / for the fraction bar. consider the given table.

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.