Thread: Math question
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Old 04-13-12, 10:34 PM   #6
Onkel Neal
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Quote:
Originally Posted by Gargamel View Post
They are the same. *Just solve for y.

Ax + By +C = 0

Becomes

y = -(A/B)x -(C/B)

So in y=mx+b

m = -(A/B)
And
b= -(C/B)

(note upper/lower case)
How did it become that second line?


Ax + By +C = 0

Subtract C from both sides:
Ax + By = -C

Subtract Ax from both sides:
By = -C -Ax

Divide both sides by B:
y = (-C -Ax)/B

How does it become:
y = -(A/B)x -(C/B) ??

I have been watching instructional videos which are great except often the person who KNOWS how to do this forgets the pupil does NOT and assumes he does.

For example, bang! Where did out friends A, B, and C disappear to??
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