help me plsss! the question is in the image. its select all that apply, so there should be more than one answer

Use the elimination method to find the solution to the system of equations. 2x - 3y = -9 -x + 3y = 6

Aheated piece of metal cools according to the function c(x) = (.5)x ? 7, where x is measured in hours. a device is added that aids in cooling according to the function h(x) = ? x ? 2. what will be the temperature of the metal after two hours?

8000 + 8800 + 8000 + 8 million + 80 trillion + another a katrillion equals