help pls... point slope form problem..

[michiksxz]

a line passes through (6,-4) and makes an angle of 135 degrees w/ the x-axis. find the eq'n of the line.

 

[wjm11]

a line passes through (6,-4) and makes an angle of 135 degrees w/ the x-axis. find the eq'n of the line.

I think you'll find this problem is easy if you draw yourself a sketch first. Where would a 135 degree angle be on an xy-graph? It would be in the second quadrant, right? This already tells us that the slope will be negative.

Sketch that line in the second quadrant. Now, what acute angle does that form with the x-axis? (Hint: the acute angle will be 180 - 135.)

So, what slope is associated with a 45 degree angle? (Hint: the "rise" and "run" are equal.)

Now that you know the slope, use that info and the point (6,-4) to write your line equation.

 

[Aladdin]

Slope = tan(alpha) .

But Slope of the line will be negative since alpha is obtuse or greater than 90 degrees.

When you find the slope it will be easy since you have a point .