3x(x+4)+15=6-4x this is for homework

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

Me, prove a quadrilateral with vertices g(1,-1), h(5,1), i(4,3) and j(0,1) is a rectangle using the parallelogram method and a rectangle method.

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?