Thread: eq lines and surd

have a picture of a line AB tht eq is y=4x-5 and passes through the point 9(2,3). The line BC is perp to AB and cuts the x axis at C. I need tofind the equation of line BC, which i have done, but i also need to find the x coordinate of C, but im not sure how do it? thnx

Also how could i express 3(in a square root thing)
--------
6-3(3 again in sqr root thing)
in the form of p+q 3(in sqroot)


Iv now with the help of you great people being able to complete my practise paper and practised and found some new tips lol thnx

Originally Posted by Chez_

have a picture of a line AB tht eq is y=4x-5 and passes through the point 9(2,3). The line BC is perp to AB and cuts the x axis at C. I need tofind the equation of line BC, which i have done, but i also need to find the x coordinate of C, but im not sure how do it? thnx

We need more information. Where does BC cross AB? There are any number of lines perpendicular to AB.

Originally Posted by Chez_

Also how could i express 3(in a square root thing)
--------
6-3(3 again in sqr root thing)
in the form of p+q 3(in sqroot)

In LaTeX code, [ math ] 6 - 3 \sqrt{3} [ /math ] (without typing the spaces between the [ ].



Is this what you are looking for?

-Dan

Originally Posted by Chez_

have a picture of a line AB tht eq is y=4x-5 and passes through the point 9(2,3). The line BC is perp to AB and cuts the x axis at C. I need tofind the equation of line BC, which i have done, but i also need to find the x coordinate of C, but im not sure how do it? thnx

Also how could i express 3(in a square root thing)
--------
6-3(3 again in sqr root thing)
in the form of p+q 3(in sqroot)


Iv now with the help of you great people being able to complete my practise paper and practised and found some new tips lol thnx

Somewhere BC intercepts AB

So the equations of the two lines become equal at some point.



Simplify that and you'll find that the D-value in is given by the following function:



Where the is the -axis value where the two lines cross. From there you'll find the D-value of f(x).

When you have that, set

Then solve for and you'll find the C-value that you're looking for.

Originally Posted by janvdl

That would be the line

-Dan

Originally Posted by topsquark

That would be the line

-Dan

Hehe, that had to happen sometime. Thanks Topsquark.