If the equations x + y = 3, X-Y = 1 and x-2my = 0 have common solutions, then the value of M is______ ．

If the equations x + y = 3, X-Y = 1 and x-2my = 0 have common solutions, then the value of M is______ ．

According to the meaning of the question, we get x + y = 3x − y = 1x − 2My = 0, the solution is x = 2Y = 1m = 1, the value of M is 1

Come and help me to solve the equation x & # 178; + 4x-3 = 0

First of all, let's see if we can use the cross multiplication in the factorization method. It's obvious that this problem can't be solved, so we should use the most primitive method formula method. First, we should judge how many roots there are in the quadratic equation of one variable by the discriminant of the root of Δ = B ^ 2-4ac. When Δ = B ^ 2-4ac0, X has two different real roots

5（x²+17)-6(x²+2x)=0 (50-x)(30+2x)=2100
5（x²+17)-6(x²+2x)=0
(50-x)(30+2x)=2100

5（x²+17)-6(x²+2x)=0
5x²+85-6x²-12x=0
x²+12x-85=0
(x-5)(x+17)=0
X-5 = 0 or x + 17 = 0
That is, x = 5 or x = - 17
(50-x)(30+2x)=2100
1500+100x-30x-2x²=2100
2x²-70x+600=0
x²-35x+300=0
(x-15)(x-20)=0
X-15 = 0 or x-20 = 0
We get x = 15 or x = 20

The number ratio of science and technology books to story books in the library is 2:3. In the morning, a batch of newly purchased science and technology books are set in the library, and after sorting, the number ratio of science and technology books to story books is 10:9. In the afternoon, the number ratio of science and technology books to story books is 5:6. Only 100 more science and technology books have been purchased than story books How many science books and story books are there?

It turns out that the ratio of science and technology books to story books is 2:3 = 6:9. In the morning, a batch of newly purchased science and technology books are set up in the library. After sorting out, the ratio of science and technology books to story books is 10:9. Therefore, the ratio of science and technology books to story books is 10-6 = 4. In the afternoon, the newly purchased story books and story books are put into the library

Quadratic arithmetic sequence 2, 5, 9, 14, 20, 27. General term formula?
What is the general term formula of quadratic arithmetic sequence 2, 5, 9, 14, 20, 27?

an = 2 + (4 + n) * (n - 1) / 2
= (n ^ 2) / 2 + 3 * n / 2

How to measure the diameter of thin copper wire?

Wind the thin copper wire tightly around a cylindrical object, such as a pencil, 100 times
Use a ruler to measure the width D of 100 turns. Divide it by 100 to get the diameter of the thin copper wire

Grade 6 Volume 1 birch text
The sea of poems in PEP Edition

Lin Hai
I always thought that the Great Xing'an Mountains were high and unreachable. This time I had a chance to see it, and walked into the primeval forest, stepped on the pine needles several feet thick, and touched the ancient trees, which proved that this pleasant name was so kind and comfortable
The word "mountain" in Daxinganling is quite different from that in Qinling. There are many mountains here, horizontal, along, higher, shorter, longer and shorter, but none of them reminds people of the dangerous sentence "Yunheng Qinling". How many mountains have been seen for several hours on the speeding train, and I can't finish or get tired of seeing them. Every mountain is so gentle, From the foot of the mountain to the top of the mountain are full of precious trees
As far as you can see, it's green everywhere. It's really the sea of forests, and the undulating mountains are the waves of the sea of forests. There are so many kinds of green colors: deep, light, bright, dark, green beyond description. I'm afraid only painters can depict so many green colors!
Larch is the first treasure in Xing'an Mountains. Yes, it's a larch sea. Look, isn't there white spray on the sea? It's some pretty birch, and the trunk is silver white. In the sun, the silver skirt of birch flickers on the edge of a large area of green pine, isn't it like the spray on the sea?
There are many wild flowers on the Bank of the river. I love flowers, but I can't name them here. How can Xing'an Mountain dress itself: green pine as a shirt, white birch as a skirt, and embroidered shoes. Even the gap between trees is not lack of color: there are all kinds of small flowers under the shadow of pine, The red bean wine produced by Xing'an Lingzhong distillery is made from these small wild fruits. It tastes very good
Seeing the countless green pines and white birches, who can not look in all directions? How many provinces and cities have used the wood here, ranging from mines and railways to rafters and columns, tables and chairs. Thousands of mountains and green trees are connected with Guangxia and Liangcai. Therefore, the more you look at Xinganling, the more lovely it is! Its beauty is integrated with construction, and it is not empty. It makes people feel kind and comfortable
When we saw the forest farm, we felt more intimate. We cut wood and protect seedlings. We cut and plant trees. We not only take treasure, but also do scientific research, so that the forest can not only be evergreen, but also be comprehensively utilized. There are many towns in the mountains and forests, which add new scenery and pleasant labor songs to Xing'an Mountains, How can it not make us feel kind and comfortable? I don't know why it was called Xing'anling at the beginning. From today's point of view, it really contains the meaning of rejuvenating the country and stabilizing the country

Least common multiple of 96 and 72

288 answers,

The ratio of 1 / 3 to 7 / 9 is equal to the ratio of 3 / 4 of X

1/3:7/9=x:3/4
7x/9=1/3x3/4
x=1/4x9/7
X = 9 / 28 / fraction line

If a + b > 0, then a > 0, b > 0
Give counter examples to show that the following propositions are false propositions. (1) if a + b > 0, then a > 0, b > 0; (2) triangles with equal area are congruent triangles. (3) quadrilaterals with four equal sides are squares. (4) equal angles are opposite vertex angles. (5) two straight lines are cut by the third straight line, and the same position angles are equal. (6) the diagonals of two sides and one of them correspond to two congruent triangles

(1) If a + b > 0, then a > 0, b > 0;
For example: a = 3, B = - 2, when a + b > 0, but B = 2