If EF = m, CD = n, then AB =?

If EF = m, CD = n, then AB =?

(1) The order of the four points is a, C, D and B
EF=EC+CD+DF=AC/2+CD+DB/2,
AC+2CD+DB=2m,
AB=AC+CD+DB=(AC+2CD+DB)-CD=2m-n.
(2) The order of the four points is a, D, C and B
EF=EC-CD+DF=AC/2-CD+DB/2,
AC-2CD+DB=2m,
AB=AC-CD+DB=(AC-2CD+DB)+CD=2m+n.

As shown in the figure, it is known that the line segment ad = 6cm, the line segment AC = BD = 4cm, e and F are the midpoint of the line segments AB and CD respectively, and EF is calculated

∵AD=6cm，AC=BD=4cm，∴BC=AC+BD-AD=2cm；∴EF=BC+12（AB+CD）=2+12×4=4cm．

There are three points a (1,2), B (1,6) and C (- 2,2) on the rectangular coordinate plane. Try to find out the coordinates of the other vertex D of the parallelogram with three points a, B and C as its vertex

Three solutions (- 2,6) (4,6) (- 2, - 2)

If a = 4x ^ 2-2x-1, B = 3x ^ 2-2x-4, compare the size of a and B

Find a parabolic equation whose focus is 3x square + 4Y square = 12 of ellipse, and the vertex is at the origin (thank you)
Find a parabolic equation whose focus is 3x square + 4Y square = 12 and its vertex is at the origin

Ellipse 3x & # 178; + 4Y & # 178; = 12
Become the standard equation
x²/4+y²/3=1
4>3
The focus is on the x-axis
c²=4-3=1
∴c=1
The focus of parabola is (1,0)
∴p/2=1
p=2
The parabolic equation is Y & # 178; = 2px = 4x

Junior one math problems (binary linear equations) on the line, the best explanation
Xiaohua's road from home to school is a section of flat road and a section of downhill road. Suppose that he always keeps a flat road and walks 60 meters per minute, 80 meters per minute downhill, 40 meters per minute uphill. It takes 10 minutes from home to school and 15 minutes from school to home. How far is Xiaohua's home from school?

Setting: it takes x min for Xiaohua to walk on the flat road, y Minj for Xiaohua to walk on the downhill road, and 2Y min for Xiaohua to walk on the uphill road
According to the meaning of the title, {x + y = 10
{ x+2y=15
By solving the equations, {x = 5} is obtained
{ y=5
The distance between Xiaohua's home and school is 60x + 80y = 300 + 400 = 700 (m)
A: Xiaohua's home is 700 meters away from the school
(solution 2) let the level road have X meters and the slope road have y meters
According to the meaning of the title, {X / 60 + Y / 80 = 10
{ x/60+y/40=15
By solving the equations, {x = 300} is obtained
{ y400
So x + y = 300 + 400 = 700
A: Xiaohua's house is 700 meters away from the school

In describing the volt ampere characteristic curve of small bulb, why is the ammeter externally connected?

Although the resistance of the ammeter is small, it will be affected when it is connected in series with the small bulb, because the resistance of the small bulb is also small

(1) Square of X - square of Y + X + y
(2)3x(a-b)+2y(b-a)
(3)x(m-x)(m-y)-m(x-m)(y-m)
(4)(2a+b)(2a-3b)+(2a+5b)(2a+b)
(5)3x(a-b)-2y(b-a)
(6) The third power of 4P (1-Q) + the square of 2 (Q-1)
(7) The m power of the square (X-Y) of AB + the square B of 2A

1、（x+y)(x-y-1)
2 (a-b)(3x-2y)
The square of 3 - (M-X) (M-Y)
4 2(2a+b)(2a-b)
5 (a-b)(3x+2y)
The square of 6 2 (1-Q) (2p-2pq + 1)
7 AB [b (X-Y) m power + 2A]

How many days are there from July 31, 2011 to December 21, 2012?

550 days

According to the regulations of the Labor Department of a city, since 2009, the average monthly working days of employees are 21 days, and the daily salary of Xiao Zhang in a certain unit is 35 yuan. The overtime salary of rest 13 is twice the original salary. If his actual salary in May is 1085 yuan, how many days did Xiao Zhang work overtime in May? Can you do it for him?

Let's suppose that Xiao Zhang added X-day classes in May. According to the meaning of the question, we get 21 × 35 + 35 × 2x = 1085. The solution is: x = 5. A: Xiao Zhang added 5-day classes in May