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passing through (-6,-4) and (-7,-8) write in slope intercept form

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2 Answers

Let us remember that the slope intercept form of an equation equals: y = mx +b, where "m" = slope of the line, and "b"= intercept of the line,
 
Now, the formula for the slope of a line can be found by,  m = (rise)/(run) = (y2-y1) / (xx-x1)
 
Substituting the values from our two points, we get
 
m = [(-8)-(-4)] / [(-7)-(-6)] = (-4)/(-1) = 4,
 
Now, we have that our equation is:   y = 4x +b
 
In order to find the value of "b", we substitute the values of any of the two points in the above formula and solve for "b",
 
y = 4x + b
-4 = 4(-6) + b
-4 = -24 + b
-4 + 24 = b, therefore,  b = 20
 
So, now our final equation looks like:     y = 4x + 20
Madario, it seems you having a hard time with lines, points, slopes...
 
Purple math has great explanations for these at
 
 
The slope intercept form is 
y = mx + b
 
But you were only given two points on the line, so first you must determine the slope this can be sloved by using the slope formula
 
m = (y1-y2)  = ((-4)-(-8))/((-6)-(-7)) = ((-4)+8)/((-6)+7) = 4/1 = 4
       (x1-x2)
 
now that you have the slope you can determine b, the y intercept, by solving for b using the calculated slope and one of the points
 
y = mx + b
 
-4 = 4(-6) + b
-4 = -24 + b
-4 + 24 = -24 + b + 24
20 = b
 
so you can now substitute in the values for m and b that you calculated
 
y = 4x + 20