# Thread: Algebraic Fractions

1. ## Algebraic Fractions

R = -0.0075t+3.85. Solve for t.

Here's my working.

R = -0.0075t+3.85
R-3.85 = -0.0075t
-t = R-3.85/-0.0075
t = R-3.85/0.0075

I thought this was correct but in the answer book on the very last step, I am wrong:

t = 3.85-R/0.0075

Why is this?

2. ## Re: Algebraic Fractions

Originally Posted by JanoD
R = -0.0075t+3.85. Solve for t.

Here's my working.

R = -0.0075t+3.85
R-3.85 = -0.0075t
-t = R-3.85/-0.0075
t = R-3.85/0.0075

I thought this was correct but in the answer book on the very last step, I am wrong:

t = 3.85-R/0.0075

Why is this?

$R = -0.0075t+3.85$

$R - 3.85 = -0.0075t$

Dividing by: $-0.0075$

$\frac{R - 3.85}{-0.0075}=t$

3. ## Re: Algebraic Fractions

Originally Posted by JanoD
R = -0.0075t+3.85. Solve for t.

Here's my working.

R = -0.0075t+3.85
R-3.85 = -0.0075t
-t = R-3.85/-0.0075
Here is your error. You divided both sides by -0.0075 and $\frac{-0.0075t}{-0.0075}= t$, not -t.

t = R-3.85/0.0075

I thought this was correct but in the answer book on the very last step, I am wrong:

t = 3.85-R/0.0075

Why is this?