Find the maximum or minimum of the following quadratic function: y = -2x2 + 4x - 1.

A. -1
B. 0
C. 1
D. 4

Question

Find the maximum or minimum of the following quadratic function: y = -2x2 + 4x - 1.
	
A.	-1
B.	0
C.	1
D.	4

luffingsails · Answer

Are you using calculus?

applied · Answer

It's for Algebra 2

luffingsails · Answer

Can you graph the function? That would go a long way in solving the problem.

mrnood · Answer

The max or min of the quadratic is at its 'vertex'

in the standard form,  y= ax^2 + bx +c
the x position of the vertex is: 

x= -b/2a

Put your values in to find the x value then put THAT value into the quadratic to find the corresponding value of y

luffingsails · Answer

But wouldn't Applied also have to find the behavior around the vertex? To know whether is was minimum or maximum?

welshfella · Answer

the negative coefficient of x^2 indicates a maximum

mrnood · Answer

@luffingsails

@welshfella has shown how to identify max or min on a simple quadratic.

However - there is only one solution and the question doesn't actually ask you to identify which it is - only where it is.

Identifying max and min on mor complex curves is normally done using calculus