Melody

Humans have 46 chromosomes in every cell of the body (except s***m and ova)

One of those is responsible for determining the s*x of the person.  This is the s*x chromosome.

Chromosomes come in pairs. So there are 23 pairs of chromosomes.

For males, just one chromosome is shorter than the others, but the other in the pair is normal length.  For females they are both normal legth.

The male s***m dertermines the s*x of the child.  If it ends up with the long chromosome (called X) of this pair the child will be a girl.  If the s***m ends up with the short one (called a Y chromosome) then the child will be a boy.

http://www.biology4kids.com/files/cell_chromosome.html

https://www.youtube.com/watch?v=xUrlreMaUrs

Just substitute the numbers in for the letters and finish it on a calculator :)

Yes

\(\frac{-x}{3}=2\\ -x=6\\ x=-6\)​

Good work :))

Hint:

What is

x/3-2x/3

The diameter of a circle is all the way across it.

The radius is half that, from the outside to the centre.

The area of a circle formula can be found on the formulary page on this site.  Or you can easily google it.   :)

Hi Thalys,

You have had a lot of explaination and we are very pleased to teach you.

It is time to think about all that we have presented to you today.

Now, I know that you CAN answer some of these questions yourself.

I know that you can do part a.   I've see you do ones just like this.

s(t) = 9000 - 600t                      

t is time in hours

s(t) is speed at time t

(a) Find the veritcal and horizontal intercepts of s(t) 

The verical intercept is where t=0

The horizonal intercept is where s(t)=0

(b) Explain what the horizontal and vertical interecept of s(t) represent in the context of this problem.

I guess I will just said that  y = 90000 ( the miles ) and x = ( 600 ) Hours ? Right ? 

No, you need to write a sentence for each one.  Think about it, draw the graph of the line using the intercepts and think about what it is telling you.

(c) Find the slope of s(t) 

This is the number in front of t in the formula

Look at the last question i answered for you. 

(d) Explain what the slope of s(t) represents in the context of this problem.

I will talk more about this after you have properly looked at the others.

NOW stop panicking and collect your thoughts.

Think about everything we have shown you this morning. (maybe night for you)   :)) 

Hi Thalys,

Omi67's answers are excellent.

I will just reiterate.

I might use a different example :/

Both yours are  the equation of lines.

Lines are oftenpresented in the form   

y=mx+b      (This is called gradient and y intercept form of a line)

m and b are just numbers.

for example    y=3x-6

In this example   m=3 and b=-6     (it is -6 because you added -6       y=3x+-6)

Now if you were going to find the y intercept in this example you could put x=0

and you would get  

y=3*0-6

y=-6

See how the tacked on "-6" IS the y intercept.   It always works this way.  

The tacked on "b" IS the y intercept.

---------------

Now slope is another name for gradient.

\(gradient (slope) =\frac{rise}{run}\)

I was going to do a whole lot more but I might leave it for the moment.

---------------------

The gradient is given by the number in front of the x (this is the co-efficient of x)

In this example  the number in front of x is 3  SO the slope(gradient) is 3

I could have written my line as 

y= -6+3x 

This is back to front.  I want the lots of x first so I am going to rearrange it.

y = -6     +3x

the terms are -6    and   +3x      

I need them the other way around

                      +3x     and    -6

SO my equations is better written as

y=+3x-6

y= 3x-6

this is now in gradient and y intercept form      y=mx+b

b, the y intercept, is -6

and 

m, the gradient (slope) is  +3

-----------------------------------------------------------------

In your example  a)

y=  100      -15x

it is written back to front

you need to put the lots of x first.  Remember that there is an invisable + in front of the 100

y = +100    -15x

y=     -15x   +100

The y intercept is the number tacked on the end, it is usually given the letter b and it is  100

The gradient is given the letter m and it is  -15

-----------------------------------------------------

You should be able to do b yourself now :))

(b). A(t) = 150000 - 300t 

I think Omi67 and I just did this one Thalys.    

I think Omi67 has just given you another example for you to look at here :/

a)

Hi everyone, could someone help me I going crazy with that !

(a) y = 3x + 24 = solve 

x = (-8,0) 

y = ( 0,24) 

Yes this is correct, good work!

EXCEPT you need to work on your notation.

x does NOT equal (-8,0) this does not make any sense.  

It is the x intercept that is (-8,0)

Mathematics is very precise, you must use the terminology correctly :)

---------------------------------------------------

b)

A(t) = 150000 - 300t 

I did : A(0) = 150000 - 300*0 = 150000

So the vertical interecpt is ( 0,150000)        CORRECT!!      

Then A(t) = 0      

0 = 150000 - 300t 

Solve for t : 0 = 150000 - 300t ( add 300t to the both side ) 

300 t = 150000 ( both side isolated by the t ) 

t = 150000 / 300 : 500 

t = 500       (this is better notation)

So the horizontal interect is ( 500,0 )   

 Right ?     RIGHT!!       

Excellent learning Thalys    :))

You have made a little careless error Omi,        

For the first one,   x=-8

2nd one:

You probaly already realize this Thaly but where Omi has written -300.0  the point is in the middle and Omi means multiply.   The point is NOT a decimal point.