Find the value of x
-7x + 4x = 9

Which of the following contains a variable?

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the plzzz write a proportion i will give you 100 points

Apyramid fits exactly inside a cube. the cube and the pyramid share the same square base, and they are both exactly the same height. the volume of the cube is 66 cubic inches. what is the volume of the pyramid? explain your answer. answer asap