<u>Answer:</u>
None
<u>Explanation:</u>
-3(2+7) = -3×9 = -27
-6+21 = 15
-21+6 = -15
Hence there is no equivalence
Answer:
54
Step-by-step explanation:
to evaluate substitute b = 18 into 3b
3b = 3 × 18 = 54
Answer:

Step-by-step explanation:
To isolate r, we're going to need to do some algebraic manipulation.

Multiply both sides by r:

Divide both sides by a:

Hope this helps!