Determine whether the graph of y = −3x2 − 4x + 10 opens up or down and whether it has a maximum or minimum point.

Question

dumbcow · Answer

Negative -> down -> max
Positive -> up -> min

jim_thompson5910 · Answer

What dumbcow is saying is that for any equation in the form $$y=ax^2+bx+c$$, the parabola will open down if $$a<0$$ or will open up if $$a>0$$. Any equation that opens downward will have a max, while any equation that opens up will have a min.

anonymous · Answer

i know that but i still cant figure out the right answer out of the options on this worksheet

jim_thompson5910 · Answer

What is the value of 'a' in this equation?

anonymous · Answer

im lost forreal now

jim_thompson5910 · Answer

Compare $$y=-3x^2-4x+10$$ with $$y=ax^2+bx+c$$, can you now see that $$a=-3$$?

anonymous · Answer

yea i think i do

jim_thompson5910 · Answer

so what does that tell us then?

jim_thompson5910 · Answer

if a < 0, then....?

anonymous · Answer

thankz i finally got it