सदस्य: Melody

Guest:
Jenifer is designing a quilt pattern. she wants to put right triangles together with ne leg being 4 cm and one acute angle of measure 40 degrees. ho log are the other two sides of the right triangle

I'll assume that your quilt is made out of right angled triangles where one side is 4cm and one angle is 40 degrees (so the other angle has to be 50 degrees)
If 4cm is the shorter side than the other side is 4.7670cm
If 4 cm is the longer side then the other side is 3.3564cm

Melody18 Des 2013

+118690

[quote="Guest"]There is a fish tank which contains 50 gallons. But every week 2.5 gallons evaporate from the tank. The owner of the fish tank adds 3 gallons every 10 days.Today after owner added 3 gallons, there are 44 gallons of water in the tank.

How much gallons water will be in the tank after owner adds 3 gallons 70 days from today.

It is best just to think of evatoration and added water seperately and put all the numbers together at the end.
So it will be 44 + added water - evaporation.

Now it is your turn to think about it.

Melody18 Des 2013

+118690

Guest:

First this isn't really a question. I think what you mean is
Factorise x^2+12x+27
You might spell factorise with a z, it depends on what country you are in.

I am not going to do your question but i will do one that is very similar.

x ²+8x+15
You have to look for 2 numbers that multiply to 15 and add to 8
Since they multiply to give a positive number, they must both be the same sign.
And, since they add to give a positive number they both must be postive.
3x5=15
3+5=8
So 3 and 5 are the numbers I want.
x ²+8x+15=(x+3)(x+5)

Now you should be able to do your one.
If you are keen maybe you would like to try
x ²+4x-12
If you are not keen then it doesn't matter.

Melody18 Des 2013

+118690

tRhodes:
is 4*-2*+4=*10*=-320

I don't understand.

Melody18 Des 2013

+118690

Beosoul:
3/5(x+2)=x-4 solve for x

the first thing that you have to do is multiply both sides by 5
Put the second side in brackets first.
Then the fraction will cancel out.
You do this and show me how much further you can get on your own.

Melody18 Des 2013

+118690

Hi Lily,
Phoenix, Arizona. I know where that is.
Do you know what a phoenix is? You probably do because there was one in one of the Harry Potter movies.
I'll tell you what I think it is.
A Phoenix is a beautiful mythical bird. (Mythical means that it make believe, like a fairy or a dragon) It lives for over 500 years and when it dies it bursts into flames. And from those flames, a new Phoenix (or Phoenix egg) emerges and lives on for the next 500 years. So in a way, the Phoenix lives for ever.
I would like to live in a city named after a magical bird. I think that would be really cool.
Here are pictures of what some people think a Phoenix would look like.
Phoenix bird.jpg Phoenix 2.jpg

Now, I want you to do these questions. They won't take you very long.
I'll do the first one because I want you to do the others the same way.

1) 25+2 = 20+5+2 = 20+7 = 27
I know you could probably take a short cut but I want you to do it my way.
2) 36+3 =
3) 41+7=
4) 54+5=
5) 21+8=

thankyou.

Melody18 Des 2013

+118690

Let's look at this one

y>x^2-6x+9

First you should recognise this as a parabola, concave up because of the invisable + in front of the x ²

x=-b/2a will give you the axis of symmetry, you can start there if you want to.
the vertex will be on the axis of symmetry so it you put in the x value that you just found into the equation you can find the y value of the vertex.

I wouldn't normally start there
I'd look for the roots of the equation, that is where it crosses the x axis, and the equation of the x axis is y=0
so you need to solve
0=x ² -6x +9
this one you can factorise and solve that way, the other one you will need to use the quadratic formula to get the roots
-3*-3=9 and -3+-3=-6 so this can be factorised to
0=(x-3)(x-3)
x=3
There is only one root so x=3 must also have been the axis of symmetry.
If there had been 2 roots you could have sketched the graph now but we still only have 1 point and we need at least 2 more.
The obvious one to choose is x=0 and you find the y value (I would do this even if I did already have 3 points)
By symmetry you can also find the y value for x=6
Now you can sketch the parabola. Remember it is > so it will be a dashed line. The actual parabola will not be included in the answer because there is no = sign.

Now you have to test a point. If (0,0) isn't on the graph this is always an easy one to choose.
y>x^2-6x+9
0>0^2-6*0+9
0>9 true or false?
It is false so you have to shade the side of the parabola that does not include (0,0)

Try graphing this one and then move on to the second one.

You might find graphing really fun when you get the hang of it. I like graphing equations.

Melody17 Des 2013

+118690

DGenovese:
It would be CosA=b^2+c^2-a^2/2bc

Yes but you need the brackets
On paper you probably had a big fraction so the brackets are implied but here you need to put the brackets in.

CosA=(b^2+c^2-a^2)/(2bc)

okay, now substitute in a, b and c in and get the value of CosA and then get the value for A.

Melody17 Des 2013

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