,

, which means is a point on the line. , which means is a point on the line, too.

Slope is equal to the change in over the change in , or rise over run.

The change in is equal to the difference in x-coordinates (also called run), and the change in is equal to the difference in y-coordinates (also called rise).

Substitute in the values of and into the equation to find the slope.

Simplify.

Multiply by .

Subtract from .

The expression contains a division by The expression is undefined.

Undefined

Undefined

Undefined

The slope of the line is undefined, which means that it is perpendicular to the x-axis at .

The final answer is the equation in slope-intercept form.

Replace by .

Find the Linear Function f(1)=-1 , f(1)=2