I am VERY confused on this question. Can someone help me?

What signals you that factoring by grouping is the best method to use when factoring a problem?

Find the height of a square pyramid that has the volume of 32 ft.³ and a base lengthof 4 feet

The length of a rectangle plus its width is 25 cm. the area is 156 square cm. what are the length and width of the rectangle? separate the answers with a comma.