Question

In which direction does the parabola open? y = –3x^2 + 5x + 10

A.

down








B.
up







C.
left







D.
right
A?

Answer 1

@dan815

Answer 2

Look at the leading coefficient, i.e. the coefficient of the second power of x.
If the coefficient is positive, the parabola opens upwards. If it is negative, it opens downwards.
In the above example, the parabola's leading coefficient is -3
Parabolas open left or right only if it is of the form
\[x=ay^2+by+c\]
i.e. x is a function of y.

Answer 3

Negative -> Sad Face
Positive -> Smiley Face :>

Answer 4

C

Answer 5

Whattt

Answer 6

@eflatt13
When the leading coefficient is negative, it is downwards.
Only when we chat, the sad faces go sideways. Usually they go up or down. :(