I'm going to try to explain my question the best I can. Okay, I had to write an equation of the line perpendicular to the given line and containing the given point. I then had to write the answer in standard form. Here is the question:

y=-5x+1; (10,0)

I know the reciprocal is 1/5. So then I used point-slope formula to find an equation of the line.
y-0=1/5(x-10) then I got y-0=1/5x-2 I then multiplied everything by 5 and got 5y-0=x-10.
I then answered it X+5y=-10, but the book says X-5y=10.
So my question is, when do you know to make it an addition/sub problem?

Question

I'm going to try to explain my question the best I can. Okay, I had to write an equation of the line perpendicular to the given line and containing the given point. I then had to write the answer in standard form. Here is the question:

y=-5x+1; (10,0)

I know the reciprocal is 1/5. So then I used point-slope formula to find an equation of the line. 
y-0=1/5(x-10) then I got y-0=1/5x-2 I then multiplied everything by 5 and got 5y-0=x-10.
I then answered it X+5y=-10, but the book says X-5y=10. 
So  my question is, when do you know to make it an addition/sub problem?

ganeshie8 · Answer

Your work is correct, till  :-
5y-0=x-10

ganeshie8 · Answer

standard form is :-
Ax + By = C

ganeshie8 · Answer

and usually, we want the x term to have positive coefficient

ganeshie8 · Answer

5y-0=x-10

so here, i wud simply subtract 5y both sides :
5y-0=x-10
-5y     -5y

0 = x-5y - 10

ganeshie8 · Answer

next i wud add 10 both sides :

0 = x-5y - 10
+10        +10


10 = x - 5y

its same as,

x - 5y = 10

ganeshie8 · Answer

im not sure if that answers ur q :o

anonymous · Answer

OH okay, I get it now. I see what I did wrong. I need to pay more attention to the signs, thanks! I wanted to subtract 0 from -10, but that should of been adding zero to 10...

ganeshie8 · Answer

looks u nailed it :D

anonymous · Answer

^_^