A quadratic equation of the form y = ax^2 + bx +c has two different real roots. This is possible if the corresponding parabola has: a) a > 0 and a vertex of (3, 0)
b) a > 0 and a vertex of (–3, 2)
c) a > 0 and a vertex of (3, –2)
d) a < 0 and a vertex of (–3, –2)

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15