C = 3b+2d is the same as 3b+2d = C
Let's isolate d. To do this, we first need to subtract 3b from both sides
3b+2d = C
3b+2d-3b = C-3b
2d = C-3b
Then divide both sides by 2
2d = C-3b
2d/2 = (C-3b)/2
d = (C-3b)/2
Take note of the parenthesis as they are very important. We want to divide ALL of C-3b over 2. We don't want to just divide -3b over 2.
The answer choices you have aren't 100% clear but I have a feeling your teacher meant to say d = (C-3b)/2 instead of d = C-3b/2 for choice A
If that assumption is correct, then the answer is choice A.
1:24 and 2:20 and 3:30 and 4:16 and 5:12
About 7.5 miles if you divide 45/3 is 15 so divide 15/2 which is 7.5
3/12 is a rational number because rational numbers can be written in the form of a/b
When you simplify 3/12, you get 1/4, which is a fraction
