Question

Select the x-coordinate of the vertex of the parabola defined by the function f(x)=-9x^2+7x+8

Answer 1

`x_v=-(b)/(2a)\\ x_v=-(7)/(2\cdot(-9))\\ x_v=(7)/(18)\\`

Answer 2

`f(x)=-9x^2+7x+8\\\\a=-9;\ b=7;\ c=8\\\\x_(vertex)=(-b)/(2a)\\\\x_(vertex)=(-7)/(2\cdot(-9))=(-7)/(-18)=(7)/(18)`