William W. answered 07/19/21
Math and science made easy - learn from a retired engineer
The point-slope intercept form? There's a point-slope form and there's a slope-intercept form. But not all three.
Point-slope:
The generic form of the point-slope form is:
y - y1 = m(x - x1) where "m" is the slope and a point is (x1, y1) so this line would be:
y - -1 = -2(x - 1) or y + 1 = -2(x - 1)
Slope-Intercept:
The generic form of the slope-intercept is y = mx + b where "m" is the slope and "b" is the y-intercept. So this line would start with y = -2x + b and then we would plug in the point (1, -1) as values of "x" and "y" so that we can calculate the value of "b":
y = -2x + b
-1 = -2(1) + b
-1 = -2 + b
1 = b
Then we plug in that value of "b" to get y = -2x + 1