Answer:
x=8
Explanation:
The picture tells us that the triangle is equilateral (this means that each angle is 60°). We can assume this because each side has been marked with the same line.
Because each angle is equal to 60°, this means that:
7x+4=60
Now solve for x:
7x=56
x=8
Ok for inequalities it's this < and > that so here's a example prob 3>2 so as my teacher used it put it "it's like the little number eats the bigger number." For negatives the one that's being eaten would be the one that's the closest to 0 so -3>-5 also alone way of doing this is to make a number line that's another way I was taught how to do these. I hope this helps you!
Construct a mid-point on segment BC
I would be happy to help with this question!
you would need to use the pythagorean theorem inputting 3.5 for a and 15 for c. after this you will need to solve for b and you should get the answer of 14.6feet
<u>Answer-</u>
<em>The correct answer is</em>
<em>∠BDC and ∠AED are right angles</em>
<u>Solution-</u>
In the ΔCEA and ΔCDB,

As this common to both of the triangle.
If ∠BDC and ∠AED are right angles, then 
Now as
∠BCD = ∠ACE and ∠BDC = ∠AED,
∠DBC and ∠EAC will be same. (as sum of 3 angles in a triangle is 180°)
Then, ΔCEA ≈ ΔCDB
Therefore, additional information can be used to prove ΔCEA ≈ ΔCDB is ∠BDC and ∠AED are right angles.