I’m pretty sure it’s D??? But it also could be B I’m sorry :( trying to help as much as possible
Since congruence and similarity for polygons is posted in a specific order, we know that angle A=angle F, side A=side F, die B=side G, and so on. Therefore, we have that angle C=angle H = 9x-7=5x+13. Subtracting 5x from both sides to separate the x using the subtraction property of equality, we get 4x-7=13. Next, we can add 7 to both sides to get 4x=20, and divide both sides by 4 to isolate the x and get x=5. Plugging that into angle C or angle H, we get that 9x-7=9*5-7=45-7=38=5*5+13.
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Answer:

Step-by-step explanation:
Given : 
We have to write which identity we will use to prove the given statement.
Consider 
Take left hand side of given expression 
We know

Comparing , we get, a= 180° and b = q
Substitute , we get,

Also, we know
and 
Substitute, we get,

Simplify , we get,

Hence, use difference identity to prove the given result.
Answer:
<em>No, he should have set the sum of ∠AED and ∠DEC equal to 180°, rather then setting ∠AED and ∠DEC equal to each other</em>
Step-by-step explanation:
Find the diagram attached
If line AC and BD intersects, then m<AED + m<DEC = 180 (sum of angle on a straight line is 180 degrees)
Given
m<AED = 16x+8
m<DEC = 76 degrees
16x + 8 + 76 = 180
16x + 84 = 180
16x = 180-84
16x = 96
x = 96/16
x = 6
Hence the value of x is 6
Hence the correct option is <em>No, he should have set the sum of ∠AED and ∠DEC equal to 180°, rather then setting ∠AED and ∠DEC equal to each other</em>