Taking both sides AB and AC of triangle ABC as sides, square ACDE is made outwards, square abgf and m are the midpoint of BC, and am vertical EF is proved

Taking both sides AB and AC of triangle ABC as sides, square ACDE is made outwards, square abgf and m are the midpoint of BC, and am vertical EF is proved

Proof: MP / / AC by m, AB by P, Ma by Q,
Then: MP / AE = AP / AF = 1 / 2;
Angle FAE + angle BAC = 180 and angle BAC + angle APM = 180, so angle FAE = angle APM;
So triangle APM is similar to triangle FAE, so angle PAM = angle AFE, and angle PAM + angle FAQ = 90, so angle AFE + angle FAQ = 90, so am (AQ) is perpendicular to ef

If 2x-3 = 1 and ax-3 = x + 1 have the same solution, then A-1=______ ．

∵ 2x-3 = 1 solution: x = 2, substitute x = - 2 into the equation ax-3 = x + 1, get: 2a-3 = 2 + 1, solution: a = 3, so A-1 = 2

_ A_ ._ ._ C_ B_ ._ ._ D_ ._ ._>

Is the "*" in the title a scale? I guess so
Let's say it's a scale, so
First, B ≠ 0, otherwise a is not an integer
Then a ≠ 0, otherwise B = 7, but the difference between AB is only 4
If d = 0, then B = - 3, a = - 7, b-2a = 7 is not satisfied
Only C is left, C = 0, then B = 1, a = - 3, exactly b-2a = 7
Answer: C

If the square of 5A - 3B & # 179; = 12, the square of a + B & # 179; = 4, find:
(1) The square of 6A - 2b & # 179;;
(2) Square of a - B & # 179;;
(3) The square of 14a + 6B & # 179;

Solution
5a²-3b³=12
a²+b³=4
Two formula addition
6a²-2b³=12+4=16
From (1), it is concluded that:
6a²-2b³=16
∴3a²-b³=8
Also 5A & # 178; - 3B & # 179; = 12
Subtraction of two formulas
2a²-2b³=12-8=4
∴a²-b³=2
14a²+6b³
=(5a²-3b³)+9(a²+b³)
=12+9×4
=12+36
=48

Can two groups of 220 V electricity be changed into one group of 380 V electricity and one group of 220 V electricity

For two groups of 220 V with different phases, the potential of two phase wires (live wires) is 380 v. note: it is two live wires with two "different phases"; one fire and one zero is single 220 v

General score: - X / a (X-Y), Y / b (Y-X)

xb/ab(y-x),ya/ab(y-x)
I wish you study every day, come on!

A series circuit of resistance and capacitance elements, the measured power P is 325w, the voltage is 220V, the current is 4.2a, how much is the resistance and capacitance?

From P = R * I ^ 2, it is concluded that r = P / (I ^ 2) = 325 / (4.2 * 4.2) = 18.4 Ω, the voltage drop on resistor ur = P / I = 325 / / 4.2 = 77.38 V, the voltage drop on capacitor UC = sqrt (u ^ 2-ur ^ 2) = (220 * 220-77.38 * 77.38) = 205.9 V, the capacitive reactance ZC = UC / I = 49.0 Ω, the voltage drop on capacitor ZC = 1 / (2 * pi * f * c), assuming f = 50hzc = 1 / (314.1

One part of a minus one part of B is equal to four. Find the value of a-2ab-b of 2A + 7ab-2b
The stationery counter of a shopping mall bought a batch of hero brand pens at the price of a yuan (a is the whole number) and decided to increase the price by 2 yuan. As the pens of this brand are of high quality and low price, they sold out quickly. When checking out, the salesman found that the total sales amount of these pens was (399a + 805) yuan. How many pens are there and how much is the purchase price?

1.
1/a-1/b=4
(b-a)/ab=4
b-a=4ab
a-b=-4ab
In the original form,
So the original formula = (- 6ab) / (- AB)
=6
two
Let's say it's X
X（a+2）=399a+805
X=（399a+805）/（a+2）=399（a+2）/（a+2）+7/（a+2）=399+7/（a+2）
Because x is an integer, 7 / (a + 2) is an integer, so a = 5, x = 400
To solve a problem with a series of equations is a quadratic equation of two variables, but the solution of the equation is a natural number. First, list the equivalence relation, and get the equivalence relation between X and A. x = 399 + 7 / (a + 2) if x is an integer, 7 / (a + 2) is also an integer, so a can only be equal to 5

220 V with 1000 Watt lamp, 50 meters long 1.0 square meters of copper wire, copper wire current how much?

P = UI
I = P/U = 1000 / 220 ≈ 4.55 (A)

A 10m long ladder leans against the wall. The vertical distance between the top of the ladder and the ground is 8m. The top of the ladder slides 1m and the low end of the ladder slides XM,
So the equation is?

Obviously, the Pythagorean theorem can obtain the projection length of the bottom of the ladder on the horizontal plane of 6m,
（8-1）²+（6+x）²=10²