What is an equation of the line that passes through the points (1, -7) and (-4, 8)?

y = -3x-4

Step-by-step explanation:

The two given points are (1,-7) and (-4,8)

We can find the slope (y2-y1)/(x2-x1): (-7-8)/(1-(-4))=-15/5=-3

We now know the slope of the equation is -3, the equation looks something like this: f(x)=-3x+c

Now we need to find "c", we can simply plug a cord in:

8=(-3)(-4)+a

a=-4

Now we know the know equation! f(x)=-3x-4

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Cheers!

y = -3x - 4

Step-by-step explanation:

Going from the first point to the second, we see that x decreases by 5 and y increases by 15.  Thus, the slope of this line is m = rise / run = -15/5 = -3.

Start with the slope-intercept formula y = mx + b.  When x = 1, y = -7, according to the first point given, and so we have:

-7 = (-3)(1) + b.  We can solve this for the y-intercept, b:  3 - 7 = b = -4

Thus, the equation of this line is y = -3x - 4.