I'm in the 9th grade and i haven't been going to school.. I just started going again and my teacher gave me a ishload of homework to make up.. so i need help since i dont know how to do any of it..
Write an equation of a line through the given point with the given slope.
1. (3,-5);M = 2
2. (1,2); M = -3
3. (3,0); M = -1
All help is appreciated.. Thanks in advance..
M is the symbol we are using for the slope, which tells how "steep" the line is on the graph. (3, -5) is an "ordered pair" where the first number is the x value of the point and -5 is the y value of the point.
Any line can be expressed in the form:
where is a point on the line, m is the slope of the line, x is the independent variable, and y is the dependent variable.
So for problem 1 we have that the slope m = 2, and . Thus:
Now solve this for y:
(TPH had a slight typo in his example here.)
The other two are done exactly the same way.
-Dan
Hello,
to set up the equation of a straight line you need 2 points: One fixed point with the coordinates and and a point P which represents every possible point of the straight line. It has the coordinates x and y.
The slope of the line is calculated by the ratio of the legs of a right triangle . You can calculate the length of those legs:
That means:
. Now multiply by the denominator:
And that's exactly the formula TPH has used.
EB
Hello, JeeFong!
Let me give you my baby-step approach . . . .
Write an equation of a line through the given point with the given slope.
If you are given a point on a line and the slope of the line,
. . there is a formula we can use.
It's called appropriately the "Point-Slope Formula".
Given a point and the slope
. . the equation of the line is: .
It's simply a matter of dropping in the facts we are given into the right slots.
Look at the formula again: .
. . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . y-coordinate . . slope . . . x-coordinate
We are given: .
. . . . . . . . . . . .
. . . . . . .x-coordinate .y-coordinate . slope
Drop these into the formula: .
And simplify: .
Got it?