Which expression is equivalent to 2 (a+2b)-a-2b?

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

Write an equation in point-slope form for the line through the given point that has the given slope (-2,-7); m=-3/2

Mr. vector door is buying two new cowboy hats all together the hats cost $75.12 the second heart cost twice as much as the first hat what is the price of the more expensive at round to the nearest hundredth