algebra(reiny)
posted by Marissa .
Hey thanks for all your help but you kinda confused me on a few:
1)Determine whether f(x)=5x^210x+6 has a maximum or minimum value and find that value
A.minimum 1
B.maximum 11
C.maximum 1
D.minimum 11
and you said the function opens up, so there is a minimum.
it occurs when x=1, and that minimum is f(1), which is 11. So the answer is D right?
2)Identify the vertex,axis of symmetry,and direction of opening for y=1/2(x8)^2+2
A.(8,2);x=8;up
B.(8,2);x=8;down
C.(8,2);x=8;up
D.(8,2);x=8;up
I picked A,here is your reasoning.vertex is ok, but how can the axis of symmetry be x=8?? Would it not go through the vertex?? So it is x=9 (always the same as the x of the vertex)
3)Which quadratic function has its vertex at(2,7)and opens down?
A.y=3(x+2)^2+7
B.y=(x2)^2+7
C.y=12(x+2)^27
D.y=2(x2)+7
4)Write y=x^2+4x1 in vertex form.
A.y=(x2)^2+5
B.y=(x+2)^25
C.y=(x+2)^21
D.y=(x+2)^2+3
Well I'm not Reiny but I can help you out with #3
I found out by plugging it into the Y=
for creating graphs on my TI83 Plus that it is A.
You should be able to do the same if you have this calculator and plug in each function. Then hit graph
For #1 contrary to what you found I found that when I plugged it into my Y= function on my calculator that the
curve faced down
at X=1 was the vertex
Y=10.9/ 11
 based on that I would have to say my conclusion is that it has a maximum at Y=11
For #2 it is D
but not x=9 like you said but I assume it was a typo
The axis of symetry is the same as the x of the vertex (your thinking is correct)
1. yes it is D
2. I clearly meant to type x=8
3. clearly A. B would have vertex (2,7), and both C and D open downwards
4. y=x^2+4x1
y = x^2 + 4x + 4  4  1
= (x+2)^2  5
Respond to this Question
Similar Questions

math
I'm having some troubles with these. Thanks in advance. If a>0 find the minimum value. If a<0 find the maximum value. 1. y=x²+2x+5 2. y=2x²3x+4 These are functions for parabolas, so f(x)=ax²+bx+c when a does not equal 0 … 
Algebra Maximum and minimum.
I don't understand how to find the maximum and minimum. Determine whether the given quadratic function has a minimum value or maximum value. Then find the coordinates of the minimum or maximum point. 15.f(x) = x2 + 2x  4 20.f(x) … 
Maximum and Minimum
Its been awhile since I have done compleating the square, can you please help me? 
ALGEBRA
Determine whether the quadratic function has a minimum or maximum value.Then find the coordinates of the minimum or maximum point. f(x)=2x^24x 
Math/Algebra...can you check this please...
f(x)= 4(x+5)^2+3 The vertex is : 5,3 The line of symmetry is x= 3 The maximum/minimum value of f(x)= 5 Is the value of f(5)=3, a minimum or maximum? 
algebra
given the following quadratic equation, determine if it has a maximum or a minimum value. Then find the maximum or minimum value f(x)  11x^2  2x  7 
Math
Can someone help me with these questions? 
math
Determine whether the given quadratic function has a minimum value or maximum value. Then find the coordinates of the minimum or maximum point.f(x) = x2 + 2x  9 
math
Maximum or minimum values of the function f(x) = (1 – x)^2 e^x is: i need solution (a) Minimum value at x = –1; maximum value x = 1 (b) Minimum value at x = 1; maximum value x = –2 (c) Minimum value at x = 1; maximum value x … 
calculus
Find the absolute extrema of the function (if any exist) on each interval. (If an answer does not exist, enter DNE.) f(x) = square root of (25 − x^2) (a) [−5, 5] minimum (x, y) = (smaller xvalue) (x, y) = (larger xvalue) …