does anyone know when im suppose to use the formula x=-b/2a or the quadratic formula when graphing?

Question

does anyone know when im suppose to use the formula x=-b/2a  or the quadratic formula when graphing?

anonymous · Answer

yes

anonymous · Answer

quadratic formula gives you the x - intercepts.  where the parabola crosses the x - axis

anonymous · Answer

$$-\frac{b}{2a}$$ gives you the first coordinate of the "vertex"  where the parabola sits. highest or lowest point on the curve

anonymous · Answer

so how would they ask me a question if i had to use the -b/2a formula? find the vertex?

anonymous · Answer

They would give you a quadratic equation and ask you to find vertex

anonymous · Answer

there asking me to solve quadratic equations by graphing, and the question is x^2 - 3x - 10= 0 what formula would i use?