Which value when placed in box would result in a system of equations with infinitely many solutions y =-2×+4

What is the length of bc ? enter your answer in the box. bc =

Emma will roll two number cubes labeled 1 through 6. she will record the sum of the two numbers after each roll. she will roll the two cubes 540 times. how many times should emma expect the sum to equal 5?

Explain how you can use the associative property to evaluate (7x50)x4.