In two propositions, if () of the first proposition is () of the second proposition and () is (), then these two propositions are called inverse propositions If the inverse proposition of a () is also (), then these two () are called (), and one () is called the () The converse proposition of a false proposition can be (), or (). For example, "equal angle is opposite vertex angle" is a false proposition, but its converse proposition "()" is () and ()

In two propositions, if () of the first proposition is () of the second proposition and () is (), then these two propositions are called inverse propositions If the inverse proposition of a () is also (), then these two () are called (), and one () is called the () The converse proposition of a false proposition can be (), or (). For example, "equal angle is opposite vertex angle" is a false proposition, but its converse proposition "()" is () and ()

The conclusion of the first proposition the conclusion of the second proposition
True proposition true proposition reciprocal true proposition inverse proposition
True propositions and false propositions are opposite to true propositions when vertex angles are equal

Can four equations and four unknowns solve the unknowns?
What conditions must be met to find out?

For example, x + y = 3, x-3 = y, x = 3-y are actually the same equation and cannot be counted as three equations

There is no air on the moon. How did Apollo get back to earth?

Because the gravity of the moon is 6 / 1 of that of the earth, Apollo lunar capsule can break away from the gravity of the moon without much thrust

The square of 9x - 6x + 1 is greater than or equal to 0

9x ^ 2-6x + 1 = (3x-1) ^ 2 > = 0 complete square formula
Hope to adopt

A car is driven to the destination 180 km away from the starting place. It will drive at the planned speed within the first hour after departure, and at 1.5% of the original speed after one hour
Double speed, and 40 minutes ahead of schedule to arrive at the destination, seek the speed of the previous hour

Set the original planned speed as V, and change the speed to 3 / 2 * V one hour after departure,
It takes (1 + T) hours to arrive, which is 40 minutes earlier than the original plan
It takes 1 + T + 40 / 60 hours to arrive
The equations are as follows
v+（3/2）*v*t=180
v*(1+t+40/60)=180
By solving the equations, we can get V, which is the solution
V = 60 km / h

If × = 5 is the solution of equation 2x-7 / 4 + x-m / 3x + 2 / 12, find the value of M
Urgent need and process

Is this an equation? Does it have an equal sign?

A car from a to B, the first hour a quarter of the whole line, the second hour less than the first hour of 3 kilometers, then there are 80 kilometers away from B. how long is the road between the two places?

The highway between the two places is x km long;
1/4x+1/4x-3+80=x;
1/2x=77;
x=154km;

Given the set a = {1, 3, 5}, set B = {2, a, B}, if a ∩ B = {1, 3}, then the value of a + B is ()
A. 10B. 9C. 4D. 7

According to the meaning of the question, if a ∩ B = {1,3}, and from the set a = {1,3,5}, then the set B = {2,1,3}, then a = 1, B = 3, or a = 3, B = 1, ∩ a + B = 4, then C

What is factorization in the range of real numbers, for example, x2-5x + 3, please ask you 3Q

X-5x + 3 can be factorized into (x - (√ 13-5) / 2) (x - (√ 13 + 5) / 2). The formula of X + (P + Q) x + PQ form can be factorized into (x + P) (x + Q) if P and Q are rational numbers. This is the usual factorization, which can be called factorization of rational number range, If q is a real number (including irrational number), it becomes the factorization of the real number range. For ax + BX + C Δ = b-4ac, it must be greater than zero before it can be decomposed into (x - (- B + √Δ) / 2a) (x - (- B - √Δ) / 2a). In fact, it uses the root formula, but the ancient root formula is derived from the above inverse formula

Apples account for three eighths, oranges account for one fifth, bananas account for two ninths and water account for three fifths of the x kg of fruit delivered by fruit shops
According to the condition, the equation is set up
Among the x kg fruits transported by fruit shops, apples accounted for three eighths, oranges accounted for one fifth and bananas accounted for two ninths. (1) fruit shops transported 36 kg apples. (2) fruit shops transported 28 kg bananas. (3) fruit shops transported 46 kg apples and oranges. (4) fruit shops transported 55 kg more apples than bananas

3/8x=36
2/9x=28
3/8x+1/5x=46
3/8x-2/9x=55