Simplify: (3x2 − 4xy + 7y2) − (7x2 − 6xy − 3y2) −4x2 − 10xy − 10y2 −4x2 − 2xy + 10y2 −4x2 − 10xy + 10y2 −4x2 + 2xy + 10y2

Rena is building a 1: 180 scale model of a real castle. her model has a rectangular base that is 3 feet wide and 4 feet long what is the area of the base of the actual castle in square feet

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.

The sum of the speeds of two trains is 720.2 mph. if the speed of the first train is 7.8 mph faster than the second train, find the speeds of each.