Find cordninates of the midpoint of the segment with each pair of endpoints

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0