Simplify. 5+ 8y^2- 12y^2+ 3y

Can someone me with the property questions for 12 13 and 14 plz

The volume, v, of a rectangular prism is determined using the formula, where / is the length, w is the width, and his theheight of the prism. carltren solves for w and writes the equivalent equation w=using this formula, what is the width of a rectangular prism that has a volume of 138.24 cubic inches, a height of 9.6 inches, and a length of 3.2 inches?

What are the solutions for the following system? -2x^2+y=-5 y=-3x^2+5