Question

What is the x-coordinate of the vertex of the parabola whose equation is y = 3x² + 9x?

o-3
o-1 1/12
o-2/3

Answer 1

Answer: x=-1,5.

Explanation:

`y=3x^2+9x\\\boxed {x=-(b)/(2a) }\\a=3,\ \ \ \ \ b=9.\\x=-(9)/(2*3)=-(3)/(2)=-1,5.`