How would I evaluate this expression?

5x^2 + 8y when x = 4 and y = -9 I got 36 but it has to be either 8, 437, 328 or -1080

I got -50... LOL! I have no idea what the ^ sign means? I've never seen that one before..

5x^2 + 8y = 5(4)^2 + 8(-9) = 5(16) - 72 = 80 - 72 = 8