What is the equation of the line between $(-9,16)$ and $(-4,12)$ ?

Question

1807 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-16T01:21:52

$(-9,16)$ and $(-4,12)$

Let's use the point-slope formula

$(y_2-y_1)/(x_2-x_1)$

$(12-16)/(-4--9)$

$(color(green)(-4))/color(blue)(5$

Now we have the slope for point-slope form, which is $y =mx+b$ with $m$ being the slope and $b$ as the $y$ -intercept, the value of $x$ when $y=0$

Let's guess:

$y=-4/5x+5$
graph{y=-4/5x+5}

Were looking for $(-4, 12)$

Nope, not quite

$y=-4/5x+5.2$
graph{y=-4/5x+5.2}

Almost

$y=-4/5x+7.8$
graph{y=-4/5x+7.8}

We're so close

$y=-4/5x+8.8$
graph{y=-4/5x+8.8}

Great! We have our equation!

$y=-4/5x+8.8$

What is the equation of the line between (-9,16)(-9,16) and (-4,12)(-4,12)?