Question

Help please

Answer 1

I have 19 problems in 20 min

Answer 2

How do I know what y is?

Answer 3

and x

Answer 4

if you were to factor y = x^2 - 6x + 9, you would get y = (x-3)^2

So it's in vertex form y = a(x-h)^2 + k where (h,k) = (3,0)...that's the vertex

Answer 5

this parabola opens upward (because the leading coefficient is positive)

the lowest point is at the vertex (3,0)

Answer 6

so that gives you an idea of what the graph looks like (a basic sense of it)

Answer 7

to find the y-intercept, you plug in x = 0 and solve for y

to find the x-intercepts, you plug in y = 0 and solve for x

Answer 8

hypotenuse = \(9\sqrt{2}\)

Answer 9

the next is 12.73?

Answer 10

\(\large \color{red}{\checkmark}\)

Answer 11

that's the approximate length, yes

Answer 12

http://www.wolframalpha.com/input/?i=vertex++y+%3D+-5x%5E2%2B280x+-+3600

Answer 13

the vertex of y = ax^2 + bx + c is (h,k) where


h = -b/(2a)

k = ah^2 + bh + c

Answer 14

in this case, a = -5, b = 280, c = -3600

so

h = -b/(2a)

h = -280/(2*(-5))

h = 28

and

k = ah^2 + bh + c

k = -5(28)^2 + 280(28) + (-3600)

k = 320

Answer 15

the wolfram alpha link ganeshie8 posted confirms the vertex to be (28, 320)

Answer 16

this is another vertex problem

now

a = -16
b = 32
c = 40

Answer 17

you need to solve

x*(2x + 8) = 24

for x to get the width

Answer 18

x*(2x + 8) = 24

2x^2 + 8x = 24

2x^2 + 8x - 24 = 0

2(x^2 + 4x - 12) = 0

x^2 + 4x - 12 = 0/2

x^2 + 4x - 12 = 0

(x + 6)(x - 2) = 0

I'll let you finish

Answer 19

since the numbers are large, and you're working with decimals, you can use a graphing calculator to solve

1317500 = -2.03x^2 + 77.85x + 742

Answer 20

oh wait, I scaled it wrong

Answer 21

skip this and move to next prolem
there seem to be a problem wid question

Answer 22

it should be 1317.5 = -2.03x^2 + 77.85x + 742

Answer 23

I forgot that N is in thousands

Answer 24

http://www.wolframalpha.com/input/?i=1317.500+%3D+-2.03x%5E2+%2B+77.85x+%2B+742

Answer 25

Thanks

Answer 26

1990 + 10 = 2000