Which of the following quadratic functions has a graph that opens downward?

Check all that apply.

A. y=2x-x^2
B. y= 1/3x^2-8x-13
C. y=2/3x^2-13x+5
D. y= -(3+x^2)

Question

Which of the following quadratic functions has a graph that opens downward?

Check all that apply.

A.  y=2x-x^2
   B.  y= 1/3x^2-8x-13
   C.  y=2/3x^2-13x+5
   D.  y= -(3+x^2)

anonymous · Answer

D as it has a negative in front of the power of 2 variable

anonymous · Answer

A and D

anonymous · Answer

D

anonymous · Answer

You are correct TMTC I overlooked a

anonymous · Answer

(A also has a negative coefficient in the x^2 term)

anonymous · Answer

HTH

anonymous · Answer

so whenever a is negative the parabola opens downward?

anonymous · Answer

Yes

anonymous · Answer

Yes.  an easy way to remember:  if the x^2 coefficient is negative, its like a frown.  If it's positive, its like a smile

anonymous · Answer

thanks!

myininaya · Answer

lol mathstututorcom

anonymous · Answer

Do you like that?  I always find it really handy to remember this.

myininaya · Answer

i like it 
its funny and cute

myininaya · Answer

kassia to see if a parabola is open downward you see if there is a negative number in front of the x^2 term

open upward if postive number in front of the x^2 term