Find the solution to the system of equations given below using elimination by addition
5x + 4y = -20
5x + 12y = -10

a. x = -5, y = 5/4
b. x = 2, y = - 15/2
c. x = -94/5, y = 7
d. x = -7, y = 25/12

Ellie spent $88.79 at the computer stote. she had $44.50 left to buy a cool hat. how much money did she originally have? write and solve an equation to answer the question.

Which expression is equivalent to 64 - 9x^2?

Brittany has designed four different birdcages, each with the same volume: a square pyramid, a cylinder, a cone, and a sphere. the zoo wants to use one of brittany’s designs but plans to change the volume of the cage. find the design change that would result in the birdcage with the greatest volume. a.) increase the area of the base of the square pyramid by a factor of ten. b.) increase the height of the cylinder by a factor of ten. c.) increase the radius of the cone by a factor of ten. d.) increase the radius of a sphere by a factor of ten.