Unit 5 please read the whole text! I forgot my book!

The text "Su Wu Yang Yang" of the sixth grade Chinese compulsory education Volume 2 of Beijing Normal University Edition?
Text content

Su Wu left Hu Festival without humiliation, snow and ice. After 19 years of hard suffering, he thirsted for snow, starved for blankets, and shepherded the north coast. He had a Han state in his heart, but he had not yet gone through all the difficulties. His heart was as strong as iron stone. Sitting on the plug at night, listening to the sound of eggplant, his ears were sad. In a twinkling of an eye, the north wind was blowing, and the wild geese were flying away, the white haired girl was looking back, and the red makeup was empty, Hang on to henderway

If there is a fraction, the numerator plus 5 can be reduced to 2 / 5, and the numerator minus 5 can be reduced to 7 / 18?
In a simpler way, I haven't learned proportion yet
The title is wrong

Let this fraction be p / Q. according to the problem: (P + 5) / Q = 2 / 3 (P - 5) / Q = 7 / 18, then we get the system of equations: 3P + 15 = 2q, 18p-90 = 7q

The necessary and sufficient conditions for the image of function y = ax ^ 2 + BX + C to pass through four quadrants (online, etc.)

1) First of all, A0 is a quadratic function. Otherwise, a quadratic function can pass through three quadrants at most
2) Secondly, there must be two intersections with the X axis, otherwise the curve will only pass through two quadrants in the half plane
That is, the discriminant should be greater than 0, that is, B ^ 2-4ac > 0
2) Again, two need to be one positive and one negative, otherwise only through three quadrants
That is, x1x2 = C / A0, C / A

Which is bigger, 7 / 8 or 8 / 9,

Find the maximum value of the function y = 3sin (x + π / 9) + 5sin (x + 4 π / 9)

Y = 3sin (x + π / 9) + 5sin (x + 4 π / 9) = 3sin (x + π / 9) + 5sin (x + π / 9 + π / 3) = 3sin (x + π / 9) + 5 / 2 * sin (x + π / 9) + (5 √ 3) / 2 * cos (x + π / 9) = 11 / 2 * sin (x + π / 9) + (5 √ 3) / 2 * cos (x + π / 9) (auxiliary angle formula) = 7SiN (x + π / 9 + θ)

How to calculate 1 / 7 / 14 / 3-8 / 5

1 / 7 / 3 / 14-5 / 8
=﹙1／7﹚×﹙14／3﹚﹣5／8
=2／3-5／8
=1／24

Given the point (3, a) (5, a) in the quadratic function y = 5x ^ 2 + kx-4k image
Find the analytic expression of this quadratic function,

In (3, a), 3 is x and a is y
In (5, a), 5 is x and a is y
Respectively into the equation, the composition of two equations, you can find the value of K
y=5x^2+kx-4k
It's a = 5 * (3) ^ 2 + 3K - 4K
And a = 5 * (5) ^ 2 + 5K - 4K
The answer on the first floor is correct. I've been thinking about the theorem for a long time, but I haven't come up with it. I'm ashamed~

How to test a substance containing hydrogen? Explain, thank you

Ignite the substance, use a dry cold beaker, and observe whether there are water drops above the flame. If there are, there is hydrogen

If (a + b) 2 = 17, (a-b) 2 = 11, then A2 + B2=______ ．

(a + b) 2 = A2 + B2 + 2Ab = 17 & nbsp; & nbsp; ①, (a-b) 2 = A2 + b2-2ab = 11 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; ②, ① + ② get: 2 (A2 + B2) = 28, ‖ A2 + B2 = 14

Unit 5 please read the whole text! I forgot my book!