Write the sum using summation notation, assuming the suggested pattern continues. -9 - 3 + 3 + 9 + + 81

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles. i'm desperate.

Ahigh definition tv cost $800 with a down payment of 2/5 of the cost. how much is left to pay, in dollars after the down payment has been made?

Which of the points a(6, 2), b(0, 0), c(3, 2), d(−12, 8), e(−12, −8) belong to the graph of direct variation y= 2/3 x?