The trend line passes through (10,9) and (35,0). Write an equation for the trend line.

Solution :  

Step 1 :

Make a scatter plot of Lily’s running data.

Step 2 :

To draw a trend line, use a straight edge to draw a line that has about the same number of points above and below it. Ignore any outliers.

Step 3 :  

Find the slope of the trend line.

The line passes through points (2, 20) and (4.5, 45).

Use the slope formula.  

m  =  (y2 - y1) / (x2 - x1)

Substitute x1, = 2, y1 = 20, x2 = 4,  and y2 = 45.

m  =  (45 - 20) / (4.5 - 2)

m  =  25 / 2.5

m  =  10

Step 4 :  

Find the y-intercept of the trend line.

Slope-intercept form equation of a line :  

y  =  mx + b

Plug y = 20, m = 10 and x = 2.  

20  =  10 · 2 + b

20  =  20 + b

Subtract 20 from both sides.  

0  =  b

Step 5 :  

Use your slope and y-intercept values to write the equation.

Slope-intercept form equation of a line :  

y  =  10x + 0

So, the equation for the trend line is

y  =  10x

Example 2 :

David records the number of chapters and the total number of pages for several books as given below.  

No. of chapters

3

4

5

8

10

11

15

17

19

No. of pages

20

44

50

95

90

130

125

170

160

Step-by-step explanation:

the solution is the point

step-by-step explanation:

we have

> equation a

> equation b

adds equation a and equation b

substitute the value of x in equation b to find the value of y

the solution is the point

answer: 414,377,008

step-by-step explanation:

just multiply it