helppp?????????

Question

This is math...

The points (3,4), (11,6), (23,9) all lie on a line... the question is calculate the coordinates of another point on this same line whose x coordinate is greater than 800.. ? I'm confused.. i used all the ways but it didn't work... please explain if you know the way .....to know the answer

Answer 1

hey you have to be patient

a straight line equation = mx+b where m=gradient b= intercept


as 3,4 is a point and 11,6
then find the gradient which is
y2-y1/x2-x1
in this case y1=4 x1=3
and y2=6 and x2=11
so 6-4/11-3
2/8=1/4
so m=1/4

and using this equation(maybe it is new but really useful) to find the equation of the straight line
y-y1=m(x-x1) so let's take (3,4)
y-4=1/4(x-4)
multiplie the equation by 4 to get rid of the quarter
4y-16=x-4
rearrange
4y=x+12

so as more than 800 as the question asks you follow these steps:
1-let's find when x=800
4y=800+12
4y=812

divide by 4
812/4=203
2-if when x=800,y=203
so the more is the x the more is the y
so y>203 when x >800
and that is the answer

so if you want 803 back to the equation

and don't forget crediting the best answer!!!!please

Answer 2

If all the points lie on a line, the slope will be the same for any pair of points. The slope is defined as the change in y divided by the change in x, so:

slope = (4-6)/(3-11) = (-2)/(-8) = 1/4
slope = (4-9)/(3-23) = (-5)/(-20) = 1/4
slope = (6-9)/(11-23) = (-3)/(-12) = 1/4

All three points have the same slope. The next thing to check is the intercept. Thus far it has been established that Y = 0.25X + B, abd "B" is the intercept.

4 = 3/4 + B, B=3.25
6 = 11/4 + B, B=3.25
9 = 23/4 + B, B=3.25

This is proof all three points lie on a line described by the formula Y = 0.25X + 3.25

If x=801, then Y = 203.5

Answer 3

A line is defined by two points. Let (3,4) be point A, and (11,6) be point B. The equation of line AB is:

(x-xA) / (xB-xA) = (y-yA) / (yB-yA)

where xA=3; yA=4; xB=11; yB=6;

So the equation is:
(x-3)/(11-3) = (y-4)/(6-4)

(x-3)/8 = (y-4)/2

x-3=4(y-4)
x-3=4y-16

The final form of the equation is: x-4y+13=0

By substituting the coordinates of the third point given, we check if our equation is correct: 23-4*9+13 = 23-36+13= 0. So it is ok.

If the x coordinate has to be greater than 800, you just take any number greater than 800 and substitute it in the equation:
for example let our point be M. So xM should be greater than 800. Let xM be 815. Then 815 - 4y+13=0. So 4y= 828, y=207.
M(815,217)

You can take any point you like and just substitute in the equation. Just be careful that xM should be greater than 800.

Answer 4

First, find the equation of the line.
(4-6)/(3-11) = -2/-8 = 1/4
y = (1/4)x + b substitute given points
4 = (1/4)3 + b => 4 = 3/4 + b => b = 13/4 So
y = (1/4)x + 13/4 Check
6 = (1/4)*11 + 13/4 = 11/4 + 13/4 = 24/4 Check ☺
Then
y = (1/4)*1000 + 13/4 = 250 + 13/4 = 1013/4
I used 1000 for x because it was easy to work with, but you can use anything you like ☺

Doug

Answer 5

take the slope of the line

rise over run


m= y2-y1/x2-x1

y=mx+b

when you draw the line you will have b (y-intercept)
when you calculate the slope, you will have m
plug in a number greater than 800 and you will get a set of coordinates

Answer 6

use slope (y2-y1)/(x2-x1)

the slope between each pair of points is 1/4; same as rise over run

1 = y2-4
-- --------
4 803-3 (i chose 803 so that you get 800 when you subtract and that's divisible by 4)

cross multiply and you'll get 200=y2-4, so add 4 and y2=204

(803, 204)

Answer 7

(803,204)