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what is the slope-intercept form for (8,0),m = -3

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3 Answers

keep a focus on the linear equation in slope intercept form

y=mx+b

put in what you know--solve for what you don't know.

so

if m=-3

and in your ordered pair (8,0)  8=x and y=0

then

0=-3(8)+b

0=-24+b

24=b

y=-3x+24

Another way: Let (x, y) be any point on the line containing (8, 0).

m = (y-0)/(x-8) = -3

Solve for y,

y = -3(x-8) = -3x + 24

 

The slope intercept form of an equation is written y = mx + b where m is the slope and b is the y-intercept (value of y when x = 0).

I am assuming that you understand that the equation is y = -3x + b, but don't know how to find b.

Two ways to solve this problem are algebraically and graphing.  To solve the problem by graphing, plot the point (8,0), then move up 3 left 1 until you reach the x-axis (x=0).

To solve the problem algebraically, substitute the given x and y values for x and y in the equation for slope-intercept and solve for b.

y = -3x + b

0 = -3 * 8 + b

0 = -24 + b

b = 24

The solution is y = -3x + 24