Quick help required plz (1 Viewer)

[sando]

I am currently revising for my test, getting most questions right, when this question which seemed quite simple has momentarily stunned me.

I think it is revision of the prelim course, which is probly why lol

Find the coordinates of the point where the line 3x -4y + 25=0 is a tangent to the circle x^2 + y^2 =25

I just need to be pointed in the right direction, thanks

 

[webby234]

y = (3x + 25)/4

x² + (3x +25)²/16 = 25

16x² + 9x² + 150x + 625 = 400

25x² + 150x + 225 = 0

x² + 6x + 9 = 0

x = -3
y = 4
There is only one pt of intersection with the circle, hence tangent.

(-3,4)

 

[webby234]

Rama, where are you getting the quadratic from?

 

[sando]

Thanks Webby. I know who to ask now if i hav a question. haha

 

[rama_v]

Rama, where are you getting the quadratic from?

Bah sorry, I read the question wrong. My mistake

 

[Shady01]

sando your tag at the bottom of your posts is the funniest most hilarious one ive ever seen. champ m8 champ
lol reminds me of me lol