What's the circumference of a circle with radius of 18 in. leave answer in terms of pie

Which of the following is the equation of a line that passes through the point (1,4) and is parallel to the x-axis a. y=1 b. y=4 c. x=1 d. x=4

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6

What are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2