X=2
-4 on both sides
4=2x
divide by 2 on both sides
X=2
If it's a regular octahedron, then you can calculate it using the formula

where

is the length of the edge.
If it's not regular, you have to calculate the area of each side individually.
Answer:
If ab=12 and a2+b2=25 then,
(a+b)2=a2+b2+2ab
a+b=√25+24
a+b=√49
a+b=7
Step-by-step explanation:
brainliest pls?
Total weight of the 8 backpacks = 8 x 14 = 112 pounds
Total weight of the 12 backpacks = 12 x 9 = 108 pounds
Total weight of all the 20 backpacks = 220 pounds
Mean weight of the 20 backpacks = 220 ÷ 20 = 11 pounds
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Answer: The mean weight of the 20 backpacks is 11 pounds
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