The formula for the area of a trapezoid is a = h(b1 + b2), where a = area, h = height, b1 = base 1, and b2 = base 2. for a trapezoid with a height of 7 centimeters and base lengths of 6 centimeters and 10 centimeters, the area is square centimeters

Solve the problem. a student earned grades of c, a, b, and a in four different courses. those courses had these corresponding numbers of credit hours: 4, 5, 1, and 5. the grading system assigns quality points to letter grades as follows: a = 4, b = 3, c = 2, d = 1, and f = 0. compute the grade point average (gpa) and round the result to two decimal places. 3.40 3.50 8.75 2.18

Asap! i'm not good math and i'm lost.

Which expression demonstrates the use of the commutative property of addition in the first step of simplifying the expression (-1+i)+(21+5i)+0