What is the reciprocal of 2/7?

a. - 3 1/2

b. - 2/7

c. 5/7

d. 3 1/2

The sum of two numbers is 86, and their difference is 20. find the two numbers

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Type the correct answer in the box. consider the system of linear equations below. rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.