the expression 2(x²-4x-21) - (x+77) and (x-7) (x+k) are equivalent. what must be the value of k A.-148 B.-71 c.83 D.160​

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

The map above shows where people live in the united states. areas that are darker blue are areas where people live close together. areas that are lighter colors are places where people live farther apart. as a geographer, if you were to study where people live and why they choose to live in these places, which of the six essential elements of geography would you be using?

Which of the following events did not occur as a result of china’s open-door policy? a. trade between japan and china was encouraged. b. all countries were given equal access to chinese ports. c. foreign influence in china increased. d. the influence of the communist party weakened.