Question 70024: Ok, i have always told me kids they can come to me with any question on homework...im in over my head here. I dont even remember working on this stuff...
If u can just direct me with a few examples i should be able to figure it out...thank you for any n all help
example of questions:
find equation of the line passing through the given points...
(1,5)(2,7) possible answers r --- y=2/3x+3 or y=1/2x-4
huh? please help me
Found 2 solutions by stanbon, tutorcecilia:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! find equation of the line passing through the given points...
(1,5)(2,7)
----------
You want an equation of the form y=mx+b where m is the slope
and b is the y-intercept.
----------
There are a couple of ways commonly used to do that.
One is called the point-slope form.
1st: you need to find the slope = [change in y]/[change in x]
=[7-5]/[2-1] = 2
2nd:Then you use the form: y-y1 = x(x-x1)
y-5 = 2(x-1)
y-5=2x-2
y=2x+3
--------------
There is another way popular in today's texts.
1st Find the slope as we did above.
2nd Substitute one of the point values into y=mx+b and solve for b
5=2(1)+b
b=5-2
b=3
Then write the equation y=2x+3
-----------
Cheers,
Stan H.
Answer by tutorcecilia(2152)  (Show Source):
You can put this solution on YOUR website! (1,5)(2,7)
Use the formula for the slope of a line:
m=
m= [plug-in the values of the two points (1,5)and(2,7)]
.
Next, use the slope-intercept formula of a line:
y=mx+b
y=any y value of the line
m=the slope of the line
x=any corresponding x value
b=the y-intercept (where the line crosses the y-axis)
.
y=mx+b [plug-in the values]
5=(2)(1)+b [plug-in the values of any one point plus and the value of the slope and solve for "b"]
5=2+b
5-2=2-2+b
3=b
.
Since we are finding the slope-intercept equation of a line, all we need to plug-in is the slope and the y-intercept: m=2 and b=3
y=2x+3
.
Check by plug-in one of the points: Try (1,5)
y=2x+3
5=(2)(1)+3
5=2+3
5=5 [checks out]
|
|
|
