SOLUTION: I am doing maths revision and i'm really stuck, i have tried the question over and over but keep getting the wrong answer. The question is: Determine the equation for a linear gra

Algebra ->  Linear-equations -> SOLUTION: I am doing maths revision and i'm really stuck, i have tried the question over and over but keep getting the wrong answer. The question is: Determine the equation for a linear gra      Log On


   

Question 892519: I am doing maths revision and i'm really stuck, i have tried the question over and over but keep getting the wrong answer.
The question is: Determine the equation for a linear graph that passes through (2,1) and is perpendicular to 2x+6y=24
My answer was y= - 1 over 3x + 5 over three
We are learning the method of y=mx+c
Please help :)
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
2x%2B6y=24, the given equation.
Solve for y.
6y=-2x%2B24
y=-%281%2F3%29x%2B4
Slope is -1%2F3. Any line in the plane perpendicular to it must have slope negative reciprocal of this value; meaning that the line you are looking for must have slope 3.

Wanting the line you are looking for to contain point (2,1), then use slope intercept form for the line you want, solved for b.
y=3x%2Bb -------- you want to know what b is, so solve for it, and then substitute the point which is supposed to be on the line you want.
y-3x=b
b=y-3x
b=1-3%2A2
b=-5-------the y-intercept.

Line you want is highlight%28y=3x-5%29.