## anonymous one year ago Use the quadratic equation y = x2 + 3x + 9. Where does the vertex of the parabola lie? (Points : 5) below the x-axis above the x-axis on the x-axis on the y-axis

1. anonymous

i think this one is A @sasogeek

2. Nnesha

$\huge\rm x=\frac{ -b }{ 2a }$ formula to find x coordinate of vetex

3. anonymous

ok thanks but i just want to know if im right or wrong @Nnesha

4. Nnesha

nope that's incorrect substitute x value y=x^2+3x+9 solve for y y is positive or negative ?

5. anonymous

i think its between B and D @Nnesha

6. Nnesha

so which one do not guess :-)

7. Nnesha

$\huge\rm Ax^2+Bx+C=0$ quadratic equation A leading coefficient C is constant term

8. anonymous

b above the x-axis @Nnesha

9. Nnesha

is that an educated guess or are u 100% sure ?? :=)

10. anonymous

thanks for the help @Nnesha

11. Nnesha

np :=)