Cheryl says that the system of equations at the right MUST be solved by elimination rather than by substitution. Explain why Cheryl is not correct.
-7x + 12y = 13
7X-11y=-9

Mary works for a company that ships packages and must measure the size of each box that needs to be shipped. mary measures a box and finds the length is 7 inches, the width is 14 inches, and the height is 15 inches. what is the volume of the box? [type your answer as a number.]

Aladder that is 20ft long is leaning against the side of a building. if the angle formed between the ladder and the ground is 75 degrees how far is the bottom of the from the base of the building?

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.