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avatar+502 

http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s11_qp_22.pdf

 

Help me in question number 18

 Jan 21, 2017

Best Answer 

 #3
avatar+502 
+5

and how did u get the y intercept

 Jan 21, 2017
 #1
avatar+99324 
+5

Let see

 

 

 

 

A(7,0)    B(5,3)   

Midpoint of AB = \((\frac{7+5}{2},\frac{0+3}{2})=(6,1.5)\)

 

equation of CB

The y intersept is 4      b=4

Draw in the right angled triangle between the points B and C and you can see  the gradient m

i.e.

\(m=\frac{rise}{run}=\frac{-1}{5}\)

so the equation of BC is

 

\(y=\frac{-1}{5}x+4\\ y=\frac{-x}{5}+4\\\)

.
 Jan 21, 2017
 #2
avatar+502 
+5

Can u tell me the general formula for the midpoint in terms of x and y

Rauhan  Jan 21, 2017
 #3
avatar+502 
+5
Best Answer

and how did u get the y intercept

Rauhan  Jan 21, 2017
 #4
avatar+99324 
0

The midpint is just (the average of the 2 x values, the average of the 2 y values)

 

To get the average of 2 numbers you add them together and divide by 2

So the average of 12 and 5 for instance is   (12+5)/2 = 17/2 = 8.5

 

If you want the more formal look,

 

The mid point of  

\((x_1,y_1)\;\;and\;\;(x_2,y_2) \;\;is\;\;\;\;(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})\)

 

 

The y intercept is where the line crosses the y axis and you can see that it crosses at  4

SO the y intercept, which is always given the letter b =4

Melody  Jan 21, 2017

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