7. The cost of 2 notebooks and 4 folders is $2.50. The cost of 1 notebook and 6
folders is $2.25. Which statement is true?
A The cost of a notebook is $1.00, and
the cost of a folder is $0.25.
B The cost of a notebook is $0.75, and
the cost of a folder is $0.25.
C The cost of a notebook is $0.25, and
the cost of a folder is $0.75.

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

What is the anwers for 9+2x=5x-3-x

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).