Question 1157258: what is the equation of a line that has a gradient of -2 and passes through the line (1, 7)
Found 3 solutions by Theo, MathTherapy, ikleyn:
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! gradient and slope are technically not the same, however, for purposes of your problem, they can be considered the same.
in your problem, the gradient is -2.
this means the slope is -2.
the slope intercept form of the equation of a straight line is y = mx + b.
m is the slope, b is the y-intercept.
slope = change in y divided by corresponding change in x = -2, in this case.
formula becomes y = -2 * x + b
use the point to find the y-intercept by replacing y with 7 and x with 1 to get:
7 = 1 * -2 + b
simplify to get 7 = -2 + b
solve for b to get b = 9
formula becomes y = -2 * x + 9
that's your solution.
replace x with 1 and solve for y to get y = -2 * 1 + 9 = 7.
the coordinate point of (x,y) = (1,7) is on the line, as it should be.
Answer by MathTherapy(10555)  (Show Source):
You can put this solution on YOUR website!
what is the equation of a line that has a gradient of -2 and passes through the line (1, 7)
Point-slope form of a linear equation: 
y - 7 = - 2(x - 1) ----- Substituting - 2 for m, and (1, 7 ) for (x, y)
y - 7 = - 2x + 2
Answer by ikleyn(52814)  (Show Source):
You can put this solution on YOUR website! .
what is the equation of a line that has a gradient of -2 and passes through the  point (1, 7).
~~~~~~~~~~~~~~~~~
I came to EDIT your post and show you how IT SHOULD BE written.
Do you see the difference ?
/\/\/\/\/\/\/\/
It is very elementary and basic skill that every student must develop to the level to solve such problems on his (or her)
own without asking assistance from outside.
To help you to develop such skills, the special lesson was created in this site
- Equation for a straight line in a coordinate plane passing through two given points
Read it and then solve your problem.
From this lesson, learn the subject once for all.
At the end of this lesson, you will find the links to other lessons, covering the entire, more wide, subject.
Do not miss these lessons.
Consider them as your textbook, handbook, tutorials and (free of charge) home teacher.
|
|
|
