the equation of a line is:
y = mx+b
where m is the slope and b the y-intercept
m = (y_2 - y_1)/(x_2 - x_1)
Using your numbers:
m = (10 - -2)/(8 - -4)
m = 12/12
m = 1 this is your slope of the line.
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But in case you need it, here's more: now we can begin t populate our formula:
y = mx + b
y = 1x + b
now we need to find our b. It is called the y-intercept or point intercept because it's the point where the line crosses the y.
You can use either set of numbers, both sets have an x and a y, and the y is the intercept.
Confusing? Well, let's do it:
(-4,-2): y = mx+b or -2 = 1 × -4+b, solving for b: b=-2-(1)(-4) thus b=2
Now with the other set of numbers:
(8,10): y = mx + b or 10 = 1 × 8+b, solving for b: b = 10-(1)(8) thus b=2
