What is the first step to solve the following system of equations using substitution? x - y = 12
2x - y = 12
A.) Add the two equations together.
B.) Solve the first equation for x.
C.) Multiply the first equation by 2.
D.) Divide the second equation by 2.

Is the square root of 4 plus the square root of 16 rational?

The base of a triangle exceeds the height by 9 inches. if the area is 180 square inches, find the length of the base and the height of the triangle.

Suppose that one doll house uses the 1 inch scale, meaning that 1 inch on the doll house corresponds to 1/2 foot for life-sized objects. if the doll house is 108 inches wide, what is the width of the full-sized house that it's modeled after? in inches and feet.