Question

Find the vertex and line of symmetry
y=-x^2+10x-34

Answer 1

Vertex=complete the square (remember)

Answer 2

vertex = -b/2a

Answer 3

-x^2+10x-34
-(x^2-10x)-34
-(x-5)^2-25(-1)-34
-(x-5)^2-9

Answer 4

Vertex= (5,-9)
Symmetry at x=5

Answer 5

@jazy well complete the square get both the solutions at a time

Answer 6

and it will be a maximum point.

Answer 7

where did you get the -25(-1)

Answer 8

That's true I guess, but I'm only in Algebra 1 so I only know the basic ways of solving these.

Answer 9

ya they are a little confusing

Answer 10

@babygirl81 that's completing the square with fast method,
I'll teach you,
For example:

x^2+bx+c
You divide 2 for 'b'

Then you get
(x+b/2)^2

Then square the b/2 and put it outside but its always negative

(x+b/2)^2-(b/2)^2+c

Answer 11

oh ok so then you multiply by -1 to make it positive, is that why you did that?

Answer 12

This is how I would have solved it:
x = -b/2a
x = -10/2(-1) btw I think this is what @.sam. put because -x = -1x
x = -10/-2
x = 5

y=-1(5)^2+10(5)-34
y= -1(25) + 50 - 34
y = -25 + 50 - 34
y = -9

(5,-9)
Line of symmetry at x=5

A LOT LONGER lol....but I'm just learning now:) The other method seems pretty short and simple though:)

Answer 13

oh ok between both of those I get it now that where the -1 came from that is a.

Answer 14

jazy did the substitution method and sam did the quick method the substitution method is a good way to learn how to do it thats how i did it before but i forgot that was a couple of chapters ago, just studying for the final