Liz Z. answered 10/02/17
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Middle school - College math tutor. I love math, and you can too!
First, put your linear equation in the standard form of y=mx +b, where m is the slope and b is the y-intercept:
5y +2x=10. We want to get y by itself, so subtract 2x from both sides:
5y = -2x + 10
Divide everything by 5 to get y by itself, and you have
5y/5 = -2x/5 +10/5, or y = (-2/5)x + 2
5y/5 = -2x/5 +10/5, or y = (-2/5)x + 2
So m = -2/5.
We need the slope of our second line (let's call that y2.) to be the negative reciprocal (negative and upside down) of our original slope.
The slope of y2 = 5/2. We can write the general equation:
y2 = (5/2)x +b. This is a different line, and it will have a different y-intercept. We can find this by plugging the point they give us in for the x and y values:
y2 = (5/2)x +b
with (3,6): 6=(5/2)(3)+b
with (3,6): 6=(5/2)(3)+b
6=(15/2)+b. You can solve for b with a calculator, or you can use fractions with like denominators:
12/2 = 15/2+b. Subtract 15/2 from both sides:
-3/2=b.
Finally, your perpendicular line has the equation of y=(5/2)x-3/2.