Posted by **Jacob** on Monday, September 22, 2008 at 10:27am.

Find the equation of the straight line joining

a)(4, 4) and ( 2, 0)

b)(3, -1), (5, 4)

i also need to know how you went about solving this problem so i can understand.. many thanks

- Math -
**bobpursley**, Monday, September 22, 2008 at 10:31am
take the generic straight line:

y=mx + b.

Put in the first point: (4,4)

4=4m+b let this be the equation 1)

put in the second point in the generic

0=2m+b

Now you have two equations, and two unknowns (m,b). Solve them. In this case subtract the second equation from the first, which yields

4=2m or m=2

This makes b=-4 check that.

- Math -
**Reiny**, Monday, September 22, 2008 at 11:47am
A slight variation of bobpursey's method for #2

slope = (4+1)/(5-3) = 5/2

let the equation be y = (5/2)x + b

sub in the point (5,4)

4 = 5/2(5) + b

8 = 25 + 2b

b = -17/2

so y = (5/2)x - 17/2

## Answer this Question

## Related Questions

- math help & correction - Problem #1 Is this correct or wrong? Find the slope of ...
- algebra - don't quite understand how to go about finding the answer to this ...
- Linear Inequality + graphing? - don't quite understand how to go about finding ...
- Maths - Point P(-8,-3)and Q(6,9)are joined by a straight line.Find the equation ...
- add maths - Find the equation of the perpendicular bisector of the straight line...
- Math(word problem) - For the line joining points A(-1, 3) and B(5, 7): a.Find ...
- Maths - Hi How can we get an equation for a straight line cause I went in many ...
- math - What strategy did you use in solving this problem? 22. Suppose that you ...
- Math -Precal 11 - Show that the point P(7,7) is on the perpendicular bisector of...
- Math - Need help solving this problem. If there's an equation at the end, need ...