Determine in which direction the parabola below opens. y = 8x2 - 3x - 9

y = ax^2 + bx + c

If a > 0, the parabola opens upwards <=

If a < 0, it opens downwards

y = 8x^2-3x-9

y+9 = 8x^2-3x

y+9 = 8 (x^2 - 3/8 x)

y+9 = 8 (x^2 - (2) (3/8) (1/2) x + (3/16) ^2 - (3/16) ^2)

y+9 = 8 (x-3/16) ^2 - 8 (3/16) ^2

y+9 = 8 (x-3/16) ^2 - 72/256

y = 8 (x-3/16) ^2 - 9 - 72/256

y = 8 (x-3/16) ^2 - 297/32

Vertex : (3/16, - 297/32)

The parabola opens upward. because 8x^2 is positive