Here's the question you clicked on:
Iplay
Which equation is not equivalent to the formula r = st a. S = r/t b. t = r/s c. s = t/r d. r = ts
Think of them like this:
And cross multiply and see what you get.
The correct answer would be C. We know this because we can divide. r=st and if we divide by s, we get t=r/s which is an example, so it tells us that it cannot be B. D cannot be the option because multiplication is associative. To eliminate the next one, just take r=st and divide by t. Once you do that, you get S=r/t, which gives you A. By the elimination process, you now know that C is not equal to r=st. You can use the process of elimination at first, but the more you work with this, it will just come naturally!