Question

-.2x^2 + 12 x + 11; solve for x

Answer 1

(-.2x + 1)(-.2x + 11)/-.2
-.2(x - 5)(-.2x + 11)/-.2
(x - 5)(-.2x + 11)

cannot solve a problem without an equality, best we can do is factor.

Answer 2

not correct

Answer 3

can you set both equal to 0 and solve?

Answer 4

use the quadratic formula

Answer 5

ybarrap your factor is incorrect

Answer 6

looks like it's right to me...

Answer 7

a is -.2
b is 12
c is 11
\[x=(-12\pm \sqrt{152.8})/-.4\]

Answer 8

anyways, since (x-5)(-.2x+11)=0, then either x-5 or -.2x+11 equal zero. Set each equal to 0 and solve for x- you will get 2 different answers

Answer 9

ok if it is correct multiply it out and you should get the original as an answer.

Answer 10

But precal, try foiling ybarrrap's final answer. It works out.

Answer 11

if you use the formula, x = -12 \[\pm\] 135.2 / -.4

Answer 12

x=60.90307428
x=-.9030742807

Answer 13

WAIT NO IT DOESN"T

Answer 14

-5*11 does not equal 11... whoops... :)

Answer 15

the last term is -5 times 11 which is -55 we need +11

Answer 16

Not everything can be factored but the quadratic formula works 100% of the time.

Answer 17

so i get -12 plus or minus square root of 135.2/ -.4. How can you even check this to see if its correct?

Answer 18

Yes graph the function and check where it crosses the x axis. It should cross at those locations.

Answer 19

Do you find the decimal of the square root? How can you graph?

Answer 20

The x values represents the solutions or roots of the functions. Do you have a graphing calculator?

Answer 21

yep

Answer 22

yes everyone is right, sep me.

Answer 23

:)

Answer 24

When I used the quadratic formula x = -12+ square root of 135.2 / -.4 or -12 - square root of 135.2/ -.4. How do I graph this?

Answer 25

Do I find the decimals of these numbers, which is -41.069 and 17.069 and graph these numers

Answer 26

The values you've determined are the values where the parabola (i.e. quadratic) crosses the x-axis (i.e. x-intercepts). Since the first term is negative (i.e. -.2), the parabola opens downward. The peak occurs between these two x-intercepts you just found. The average of these two intercepts is where the peak occurs (i.e. x = 30, y = 191)

Answer 27

Knowing this information, you can write your quadratic in the form of a parabola (this is exactly your equation): 191.-0.2 (x-30.)^2 = y

Answer 28

The vertex (max point, point of symmetry) is (30,191)

Answer 29

Parabolas are similar, just like triangles. They scale and keep their "figure", just like triangles. This should not be a surprise since Parabolas are derived from the parallel lines to the side of a right-circular cone -- looking at a cone on edge, it's a triangle.

Answer 30

So if you use this equation to model the expected number of ticket sales for each day, how do you answer with a square root or do you make it a decimal?

Answer 31

If x is the number of days, and y the number of tickets then plug in x > 0 and solve for y. Only allow y > 0 for your answer. No other conversion or restriction required.