The slope-intercept form of a linear equation is given by the equation y = mx + b, where m is the slope of the line and b is the y-intercept (the point at which the line crosses the y-axis).
Given that the slope of the line is 1 and it passes through the point (8, –1), we can use the point-slope form of a linear equation to write the equation in slope-intercept form. The point-slope form is given by the equation y - y1 = m(x - x1), where (x1, y1) is a point on the line and m is the slope.
Substituting the values given in the problem into the point-slope form, we get:
y - (-1) = 1(x - 8)
Expanding the right side and rearranging the terms, we get:
y + 1 = x - 8
y = x - 9
This is the equation of the line in slope-intercept form. The y-intercept is (-9, 0), which is the point at which the line crosses the y-axis.