I need an answer to this?

Question

What is the equation of the line that contains the points with (x,y) coordinates (–3,7) and (5,–1) ?

i need to know how to work it out..not the answer....

and also...whts the thing..i forgot how it is..

x= -b+- (square root) of bsquared minus 4ad..all over 2a??

is tht how tht goes....?

Answer 1

go to google or yahoo to do research..no easy answers here...

Answer 2

Y=-1-7

     5+3

    

Answer 3

The line through two distinct points (x1, y1) and (x2, y2) is given by

y = y1 + [(y2 - y1) / (x2 - x1)]·(x - x1)

but I don't think this is the formula you are learning, or the way you are learning it.

This is the 2-point slope formula:

  y-y1     y2-y1

  ------ = -----------

  x-x1     x2-x1          

so let's say (x1, y1) = (-3, 7) and  (x2, y2) = (5, -1)

so

(y-7)/(x- -3) = (-1 -7)/(5- -3)

simplify the right side and you get

(y--7)/(x+3) = -8/8

or

(y-7)/(x+3)= -1

Next, solve for Y.  The first step in this one is to multiply both sides by (x+3).

y-7 = -1(x + 3)   From here, multiply out the right side...

y-7 = -x -3   then add 7 to both sides.

y = -x +4

     This is in your y = mx + b where m (-1) is slope and

      b (4) is the y-intercept.

The second thing you're asking about is called the quadratic formula.

Given aXsquared + bX + c = 0

x = -b +- square root of (bsquared - 4ac)

      ----------------------------------------...

                   2a

(sorry this doesn't line up right...only the right side is divided by 2a)

The quadratic formula deals with parabolas, amongst other things.