Simple math problem

Write the equation for a line that passes through the points (3, -3) and (-1, -1)

how do you do this

Equation for a straight line is either y-y1 = m(x-x1) or y=mx+c

To find the gradient (m) you do dy/dx

difference of y/ difference of x = -3-(-1)/ 3-(-1) = -2/4 = -1/2

So the gradient is minus a half.

Put the gradient and then the coordinates into the equation, I'll use the coordinates (-1,-1). It doesn't matter which because the line goes through both.

y - y1 = m( x - x1)

y - (-1) = -1/2 ( x - (-1)

y + 1 = - 1/2 (x + 1)

You could then expand the right hand side and rearrange it to make it look prettier but that's pretty much it. I hope I've done this right :)

simple
for example

Find the midpoint between (–1, 2) and (3, –6).

Apply the Midpoint Formula:

midpoint is (1, -2)

So the answer is P = (1, –2).

First find slope
m=-1+3/-1-3=-1/2
eqn:
y-(-3)=-1/2(x-3)
y+3=-1/2(x-3)