Because f(x)+1 is shown on the graph, not f(x). Here you need to think backwards and ask yourself if f(x)+1 has a y-intercept at y = 2, then f(x) has a y-intercept at 1. And also if f(x)+1 crosses (1,4), then f(x) must cross (1,3)...
Because f(x)+1 is shown on the graph, not f(x). Here you need to think backwards and ask yourself if f(x)+1 has a y-intercept at y = 2, then f(x) has a y-intercept at 1. And also if f(x)+1 crosses (1,4), then f(x) must cross (1,3)...