Question

Find an equation of the line that contains the point (2 ,5) and is perpendicular to the line y equals one half x plus 4. Use ZStandard followed by ZSquare with a graphing calculator to verify the equation.

Answer 1

y = -2(x -2) +5

Explanation:

The slope of the given line is 1/2, so the slope of the perpendicular line will be the negative reciprocal of that: -1/(1/2) = -2.

In a version of point-slope form, the equation of the line through the given point can be written as ...

y = m(x -h) +k . . . . . for slope m and point (h, k)

For our slope of -2 and point (2, 5), the equation is ...

y = -2(x -2) +5

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Not every graphing calculator has "ZStandard" or "ZSquare".