# Math Insight

### Applet: An affine function of one variable

The affine function $f(x)=ax+b$ is illustrated by its graph, which is the green line. Since $f(0)=a \times 0 +b=b$, the graph always goes through the $y$-axis at the point $(0,b)$, which is illustrated by the gray point. You can change $f$ by typing in a new values for $a$ or $b$, or by dragging the blue points with your mouse. The parameter $a$ is the slope of the line, as illustrated by the shaded triangle.

Applet file: affine_function_one_variable.ggb