Question

Which equation is a quadratic equation? y + 3 = -2x + 5 - 8x y + 2x = -2x(4 - 3x) + 4 6x3 + y = (2x - 2)(3x + 7) 9x - y = (3x2 + 1)(5x - 1) + 4x

Answer 1

can u write the equations separately ?

Answer 2

excuse me @UserA113 post ur question separately please

Answer 3

i dont know how to post a picture
tho :/

Answer 4

dont post the pic in the ques its impossible so first post ur ques then post the pic in the reply column just like u did in this ques

Answer 5

Which equation is a quadratic equation?

y + 3 = -2x + 5 - 8x
y + 2x = -2x(4 - 3x) + 4
6x3 + y = (2x - 2)(3x + 7)
9x - y = (3x2 + 1)(5x - 1) + 4x

Answer 6

sorry!

Answer 7

@UserA113

Answer 8

uhm... Can you help with mine?

Answer 9

ya sure let me think first :)

Answer 10

oh thank you!

Answer 11

in the 3rd equa is that \[6^3\]or 6x3

Answer 12

6x^3

Answer 13

so i dont think any of these is a quadratic equation because quadratic equation is something
\[x^2+11x+28=0\]

Answer 14

those are the answers though..what should I do?

Answer 15

:/

Answer 16

oh Im screwed :(

Answer 17

\[\Large
y + 3 = -2x + 5 - 8x \\ \Large
y + 2x = -2x(4 - 3x) + 4 \\ \Large
6x^3 + y = (2x - 2)(3x + 7) \\ \Large
9x - y = (3x^2 + 1)(5x - 1) + 4x \\
\]The highest power of x in the first one is just 1. (not a quadratic)
The highest power of x in the third one is 3 due to x^3 on the LHS. (not a quadratic)
If you mentally multiply it out, the highest power in the fourth one is 3 which comes from multiplying 3x^2 and 5x which is 15x^3 (not a quadratic).

But in the second case, the highest power is 2 which comes from multiplying (-2x) and (-3x) which is 6x^2. This is a quadratic equation.

Answer 18

oh That makes sense! Thank you! Can you help me with another one?

Answer 19

I can try one more.

Answer 20

Identify the vertex for the graph of y = -2x2 - 12x + 5.

(3, -13)
(-3, -13)
(-3, 23)
(3, 23)

Answer 21

In ax^2 + bx + c, the x-coordinate of the vertex is -b / (2a).
So what will be the x-coordinate of the vertex in -2x^2 - 12x + 5 ?

Answer 22

2?

Answer 23

-2x^2 - 12x + 5
a = -2, b = -12, c = 5
what is -b / (2a)?

Answer 24

@aum can u help me with my ques

Answer 25

12? so the answer is 6a?

Answer 26

I can try after I finish this one.

Answer 27

ok http://openstudy.com/study#/updates/53c5c3bbe4b05c273e9de835

Answer 28

oh...I don't mean to be rude but after sheelo can you keep helping me? Because you help a lot

Answer 29

-2x^2 - 12x + 5
a = -2, b = -12, c = 5
-b / (2a) = -(-12) / (2 * -2) = 12 / -4 = -3.

Put x = -3 in -2x^2 - 12x + 5 to find y.

Answer 30

ya its ok @aum can help me after he/she finishes ur ques

Answer 31

11x^2?

Answer 32

@sheelo_mughal : Looks like others have already answered the questions you have posted si far in that link. If you have more post them there and I will take a look.

@lehmonyo : I will have to log off shortly after answering her question.

Answer 33

oh alright :(

Answer 34

Put x = -3 in -2x^2 - 12x + 5 to find y.
-2(-3)^2 - 12(-3) + 5 = ?

Answer 35

I thought it was 11x squared

Answer 36

Where did you get the 11x^2 from?

Answer 37

from the equation

Answer 38

In the problem the given equation is: y = -2x^2 - 12x + 5.
We found the x value from -b/2a which is -(-12) / (2*(-2)) = 12/-4 = -3
We need to find y. Put x = -3 in y = -2x^2 - 12x + 5.
y = -2(-3)^2 - 12(-3) + 5
y = -18 + 36 + 5 = 23

So the vertex is at (-3, 23)

Answer 39

ohhh alright thank you. Do you have to leave now or..?