Write the equaition of the line through the points (-5,-7) and (-6,-4).
A) 12; y=11*x+69
B) 11; y=12*x+68
C) 11; y=11*x+69
D) 12; y=12*x+68
You can solve this in two ways
Slope - intercept Formula
y = mx + b, where m = slope and b = y- intercept
Formula for the Slope (m)
m = ___________
Given two point , we solve for the slope
(-5,-7) = (,)
(-6,-4) = (,)
Substitute to the formula of the slope
-4 - (-7)
m = ___________
-6 - (-5)
-4 + 7
m = ___________
-6 + 5
3
m = ___________ or -3
-1
Then solve for b (y - intercept) by using the formula slope-intercept form
(x,y) = (-5,-7) or (-6,-4), m = -3
we use (-5, -7) for (x,y)
y = mx + b
-7 = -3(-5) + b
-7 = 15 + b
-7 - 15 = 15 - 15 + b
-22 = b
Now we have m = -3 and b = -22
Equation of the line
y = mx + b
y = -3x - 22
Equation of the line in standard form
y = -3x - 22
3x + y + 22 = 0
Note i don't know why the answer is not in the choices.