Question

solve for r in the equation C=2d-2r

Answer 1

what did you get

Answer 2

I kept getting an answer that wasn't there

Answer 3

i kept getting (c-2d)/-2=(-2r)/-2
which i simplified to (c/-2)d=r
but that cant be right since that wasnt an answer choice

Answer 4

here is a similar example if you're completely stuck

\[\large 2x-3y = 5\]

solve for y

\[\large 2x-3y = 5\]

\[\large -3y = 5-2x\]

\[\large y = \frac{5-2x}{-3}\]

\[\large y = \frac{-5+2x}{3}\]

Answer 5

its not that i don't know how to do these types of questions, im actually fairly comfortable with it, i just cant seem to get a "correct" answer; either im right and the question is wrong, or (more likely) the question is legitimate and im wrong and keep making some simple mistake @marissalovescats @phi

Answer 6

Hey. The best of the best make simple mistakes. The more practice you get, the better you will get :)

Even I forget stuff like a negative times a negative is a positive. Haha.

Answer 7

is that what i did wrong? id i forget a sign change somewhere?

Answer 8

No.. I was just showing an example of mistakes I make :P

Answer 9

Whats the 1st step you should do with

C=2d-2r to get r alone?

Answer 10

i kept getting (c-2d)/-2=(-2r)/-2
which i simplified to (c/-2)d=r

the first part is ok
\[ \frac{c-2d}{-2} = r\]

Answer 11

@marissalovescats subtract 2d from both sides which gives me C-2d=-2r

Answer 12

Yup

Answer 13

the second part simplified to (c/-2)d=r
looks dubious

you could say c/-2 + -2d/-2 = c/-2 + d

but if we start with
\[ \frac{c-2d}{-2} = r \]
and don't see this choice. try multiplying -1 top and bottom
\[ \frac{-(c-2d)}{2} = r \\ \frac{-c+2d}{2} = r\]

Answer 14

oh. i feel like i could have totally done that. giant help, everyone!