Reflecting a function across the x-axis changes every y-value to its opposite. That is, f(x) = 18x becomes g(x) = -18x.
Shifting a function upward 8 units adds 8 to every y-value. That is, g(x) becomes g(x)+8.
The combined effect of these two transformations on f(x) is to give you ...
... g(x) = -18x + 8
You recognize this as the equation of a line in slope-intercept form, with the y-intercept being +8. That is, g(0) = -18·0 +8 = 8. The y-intercept is ...
... (0, 8)
The domain and range of any linear equation is "all real numbers," that is, ...
... (-∞, ∞).
