How to write an equation in standard form of a line that passes through two points?

Question

More specifically

(-7,8) and (0,-8)

Answer 1

You know that a line has the form of y = mx + b.  So it's just a matter of finding the slope and y-intercept.  They give you the y-intercept, because they show you the y value for when x=0.  So b = -8.  The slope is just rise over run, or change in y over change in x.  So it's (8 - (-8)) / (-7 - 0) = -16 / 7.  That's m.  Now just rewrite y = mx + b in the standard form of Ax + By = C.

Answer 2

find the slope and then use the point-slope form.

slope = ( -8 - 8)/ ( 0 - (-7))

slope = - 16 / 7

y - (-8) = ( - 16 / 7 ) ( x - 0 ) pt-slope form

y + 8 = ( - 16 / 7 ) x

y = ( - 16 / 7 ) x - 8   slope- intercept form

Answer 3

it's y=mx+b

the y-intercept is where the b is and in your grid, it's -8 because that's where the y is on the 0 of your x axis. so its

y=mx+-8

you subtract -8 and 8, so the answer is -16 then subtract 0 and -7 which is 7. then, divide it. -16/7= -2.2857143, that's m. you can also simplify it to 2. so the equation is

y=2x+-8