Answer:
D) b = 
Step-by-step explanation:
First, move all the terms that do not include b to the left side with S:
S = 2ab + 2bc + 2ac
S - 2ac = 2ab + 2bc
Now, factor out 2b from the right side:
S - 2ac = 2b(a + c)
Divide both sides by 2(a + c):
b = 
Finally, multiply out the denominator:
b = 
<em>If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up (+1).</em>
<em>If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down (no change).</em>
81.1<u>3</u>9 ≈ <u>81.1</u>
Square root each side
x-5=positive/negative 9
x=14, and -4
1 hr = 60 mins
10 hr = ... mins
600 mins + 39 mins = ... mins
639 mins + 24 sec=......mins
91 cm × 24 = ...
IDK what convention factors are tho...