What is the Chinese meaning of the English abbreviation "ext"?

What is the Chinese meaning of the English abbreviation "ext"?

ext.
ABR
1.=extension
2.=exterior
3.=external
4.=extra
5.=extract

What is the Chinese meaning of the English abbreviation CCTV

China Central Television

What is the Chinese meaning of UFO

Unidentified flying object

Who can help me solve three equations ~ 1,6 (x + 2) = 2 (2x + 7) 2102-6 (4x + 9)
3100-2 (x-1) = 10, do me a favor,

1,6(x+2)=2(2x+7)
6x+12=4x+14
6x-4x=14-12
2x=2
x=1
2,102-6(4x+9)
3,100-2(x-1)=10
100-2x+2=10
-2x=10-100-2
-2x=-92
x=46

Calculate the following question (- 3) - (+ 8) 2 / 3 - (- 1 / 9) - 4.5 - (- 3.5) (- 1) - (+ 3 / two fifths) - (- 4 / three fifths)

（-3）-（+8）
=-3-8
=-11
2/3-(-1/9) -4.5-（-3.5）
=2/3+1/9-4.5+3.5
=6/9+1/9-1
=-2/9
(- 1) - (+ 3 / two fifths) - (- 4 / three fifths)
=-1-(3+2/5)+(4+3/5)
=-1-3-2/5+4+3/5
=1/5

The speed of solving the equations is fast 3x-2y = 3 ① 2x-y＝-5… ②

3x-2y＝3 ①
2x-y＝-5
4x-2y=-10 ②
① - x = 13
x=-13
Substitute x = - 13 for 2x-y = - 5
It is - 26-y = - 5
y=-21

Simple calculation of (111 + 125 + 125 + 125) × 8

Original form
=（111+125×3）×8
=111×8+（125×8）×3
=888+1000×3
=888+3000
=3888

As shown in the figure, AB is the diameter of ⊙ o, and the chord CD ⊥ AB is at point E. if AB = 10, CD = 8, find the length of AE

Connect AC, BC
∵ AB is the diameter
∴∠ACB=90°
CE²=AE*BE=AE*(AB-AE)=AE*AB-AE²
AE²-AE*AB+CE²=0
∵CD⊥AB
∴CE=CD/2=8/2=4
AE²-10AE+16=0
AE = 8, or AE = 2

When Xiao Gang was calculating the division, he wrote the divisor 72 as 27. The result showed that the quotient was 26 and the remaining 18. What's the correct quotient?

26*27+18=720
720/72=10
A: the correct quotient is 10

As shown in the figure, in △ ABC, the vertical bisector De of AB intersects AB at D and BC at E. if CE = 3cm, calculate the length of be

∵ - C = 90 °, ∵ BAC = 60 °, ∵ B = 90 ° - 60 ° = 30 °, ∵ De is the vertical bisector of AB, ∵ AE = be, ∵ BAE = ∵ B = 30 °, ∵ CAE = ∵ BAE, ∵ de = CE = 3cm, and ∵ B = 30 °, ∵ be = 2DE = 2 × 3 = 6cm