SOLUTION: I have a graph plotted (7,5) and (8,3) , horizontal axis is D and vertical axis is P. i need to get the equation of the line joining these points, i.e) P= 1d

SOLUTION: I have a graph plotted (7,5) and (8,3) , horizontal axis is D and vertical axis is P. i need to get the equation of the line joining these points, i.e) P= 1d - 2 but it isnt that a

Question 49042: I have a graph plotted (7,5) and (8,3) , horizontal axis is D and vertical axis is P. i need to get the equation of the line joining these points, i.e) P= 1d - 2 but it isnt that and i cant work it out, any help would be appreciated.
Answer by rchill(405) (Show Source): You can put this solution on YOUR website!
If you have two points, you can determine the equation of a line in the form of y=mx+b, where m is the slope. The slope, m, is defined as . It doesn't matter which ordered pair is , and , because you'll get the same answer. Using substitution we get which reduces to m=-2. So our formula so far is y=-2x+b. To find out what b is, substitute one of your points (both x and y) into the equation; using the first ordered pair we get 5=-2*7+b, which simplifies to b=19. So the equation is y=-2x+19. Note that you'll get the exact same if you were to use the other ordered pair.

Because you need the equation with D and P instead of x and y, the formula becomes .
RELATED QUESTIONS
What is the slope of the line described by this equation: P = 3 - (1/6)Q? The variable P... (answered by vleith)

I have been going over this question for an hour now and i just can't seem to get it.... (answered by checkley71)

Given are five observations for two variables, x and y. xi 1 2 3 4 5 yi 2 8 6 11 13... (answered by ikleyn)

Can someone help me on this graph? I need to give the coordinates of the point... (answered by funmath)

what is the equation of the ellipse with center (-2,-7), horizontal axis 8, and vertical... (answered by stanbon)

Can someone help me graph this equation? I need a straight-line graph. Using x-axis... (answered by phillv)

two variable quantities x and y are related by equation y=a(b^x),whwre a and b are... (answered by josgarithmetic)

Have a good idea on how to graph this equation. h= -2t^2. h is the vertical axis and t is (answered by josmiceli)