Answer:

Step-by-step explanation:
Let points D, E and F have coordinates
and 
1. Midpoint M of segment DF has coordinates

2. Midpoint N of segment EF has coordinates

3. By the triangle midline theorem, midline MN is parallel to the side DE of the triangle DEF, then points M and N are endpoints of the midsegment for DEF that is parallel to DE.
Answer: x=3
Step-by-step explanation: Step 1: Simplify both sides of the equation.
21x−5=7+17x
21x+−5=7+17x
21x−5=17x+7
Step 2: Subtract 17x from both sides.
21x−5−17x=17x+7−17x
4x−5=7
Step 3: Add 5 to both sides.
4x−5+5=7+5
4x=12
Step 4: Divide both sides by 4.
= 
So Final Answer: <u>x=3</u>
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<u>If I Helped, Please Mark Me As Brainliest, Have A Great Day :D</u>
Answer:
Option A is correct.
Solution for the given equation is, 
Step-by-step explanation:
Given that : 
Let 
then our equation become;
.....[1]
A quadratic equation is of the form:
.....[2] where a, b and c are coefficient and the solution is given by;

Comparing equation [1] and [2] we get;
a = 2 b = -1 and c =-1
then;

Simplify:

or


or
and 
Simplify:
y = 1 and
Substitute y = cos x we have;

⇒
and

⇒
The solution set: 
Therefore, the solution for the given equation
is, 
All real numbers above -4
Answer:
v=12
Step-by-step explanation:
180-12v+13v-50+38=180
168+v=180
v=12