Posted by **L.Bianchessi** on Friday, March 9, 2012 at 7:45pm.

find the point on the line y=2x-1 which is closest to the point (2,-1).

I used distAnce formula and got

D= (square root 5x^2 -4x +4)

I did....

D=square root (2-x)^2 + (-1-(2x-1))^2

What do I do now?

- precalc!!!!! -
**Reiny**, Friday, March 9, 2012 at 9:07pm
The point would be the intersection of y = 2x-1 with the perpendicular to that line passing through (2,-1)

slope of y = 2x-1 is 2

so the slope of the perpendicuar is -1/2

and the perpendicular is

y = (-1/2)x + b, with (2,-1) on it

so -1 = (-1/2)(2) + b

b =0

so intersect y = 2x-1 with y = (-1/2)x

2x - 1 = (-1/2)x

4x - 2 = -x

5x = 2

x = 2/5

then y = (-1/2)(2/5) = -1/5

the point is (2/5 , -1/5)

## Answer this Question

## Related Questions

- 7th grade math Ms. Sue please - 2. Shelly sews a blanket that has an area of 170...
- Math - 1. Rosa, Roberto, Andrea, and Inno find an estimate for square root 10. ...
- Algebra - Use the quadratic formula to solve the equation. Give exact answers: ...
- Math Help! - Four students worked to find an estimate for square root 22. Who is...
- Math ~CHECK MY ANSWER~ - 1) Which of these is a rational number? a. Pi b. Square...
- Geometry - Martin wants to use coordinate geometry to prove that the opposite ...
- Calculus - A rectangle is bounded by the x axis and the semicircle = square root...
- Algebra - A winch is used to tow a boat to a dock. The rope is attached to the ...
- college pre-calculus - simplify: square root (4/3)-square root (3/4) A. 2-...
- 7th grade math Ms. Sue ASAP please - Ms. Sue, sorry to keep bugging you with ...

More Related Questions