A. 25 = (.5 * 22) + (2 * x)
B. 25 = (.5 * 22) + (2 * x)
25 = 11 + 2x
14 = 2x
7 = x
C. 7
Answer:
students 150
adult 550
Step-by-step explanation:
x + y = 700
5x + 2y = 3050
x = 700 - y
5(700 - y) + 2y = 3050
3500 - 5y + 2y = 3050
-3y + 3500 = 3050
-3y = 3050 - 3500
-3y = -450
y = -450 / -3
y = 150
x = 700 - y
x = 700 - 150
x = 550
1 step: 
,

, then

.
2 step: 
, then




and

will have form

.
3 step: Solve this system

and dividing first equation on second we obtain

. So,

and

,

- the common ratio.
4 step: Insert

into equation

and obtain

, from where

.
Answer:
Construct MN.
Since M is the midpoint of OA, OM = MA
Similarly, N is the midpoint of OB.
Thus, ON = NB.
Now, in Δs OMN and OAB,
∠MON = ∠AOB (common angle)
(sides are in proportional ratio; OA = 2OM and OB = 2ON)
∴ Δs OMN and OAB are similar (2 sides are in proportion, with the included angle)
Since they are similar, then ∠OMN = ∠OAB (corresponding angles of similar triangles are equal)
But since ∠OMN = ∠OAB, then that means MN || AB (corresponding angles of two lines must be equal since they also sit relative to the transverse line, OA)
Thus, AB || MN (QED)