North america burned 4.5 x 1016 btu of petroleum in 1998. at this rate, how many btu's will be burned in 9 year?

The sum of the product of 4 and x and the product of 7 and y is 61. the sum of the product of 12 and x and the product of 21 and y is 61. what are the values of x and y?

Which of these tools or constructions is used to inscribe a hexagon inside a circle?

The perimeter of a rectangular lot of land is 436 ft. this includes an easement of x feet of uniform width inside the lot on which no building can be done. if the buildable area is 122 ft by 60 ft, determine the width of the easement. select one: a. 9 feet b. 18 feet c. 4.5 feet d. 7 feet