Four mixed arithmetic problems of rational numbers in Grade 7, To 80 is enough, the best is original, because I basically find online almost, ha ha In addition, there should be four items: addition, subtraction, multiplication and division. There can be less addition and subtraction, but there must be multiplication and division, and there must be negative numbers, Come on, before school starts Of course, the more the better

[(-18+28)×100]²÷200
（-260）×（-1／13）
（33－3）×（－11）
You can make it up yourself

Application of rational number addition and subtraction

Use the addition of rational numbers to solve the following problems
1. Uncle Wang took 550 yuan in cash when he went to the street, 260 yuan for shopping and 150 yuan for bank. How much cash does Uncle Wang still have?
2. The submarine originally stopped at 800 meters below the sea level. First it went up 150 meters and then it went down 200 meters. At this time, how many meters below the sea level is the submarine?

I can't figure this out. Please help me
It is known that 3a-5b + 19 = 0, a + 8b-1 = 0. Find the value of 4a-26b

A=1-8B
1-8B-5B+19=0
20-13B=0
B=20/13
Dai Ren a-8b
A=1-8*20/13
=
=
Replace A. B with 4a-26b
That's fine

Let a > 1, the definition field of the absolute value of the function y = ㏒ ax is [M, n] (m)

In the coordinate plane, we first draw the graph of the function f (x) = logax,
Then the part of the image below the x-axis is "folded" to the top of the x-axis,
The image of the function g (x) = | logax | is composed of F (x) and the part of F (x) which is not below the X axis,
∵g（1）=0,g（a）=g (1a)=1,
According to the graph, to make the value range of function g (x) be [0,1],
Its definition domain may be [1a, 1], [1, a], [1a, a],
And 1-1a = a-1a < A-1,
Therefore, combining with the meaning of the title, we know that 1-1a = 56,
a=6．

Find the monotone increasing interval of quadratic function f (x) = - 4x ^ 2 + BX + C, and prove that

f(x)=-4x^2+bx+c
Axis of symmetry: x = B / 8
Because a = - 4

The equation of finding a line which is parallel to the line 2x + 3Y = 0 and whose intercept on the y-axis is - 3

It is parallel to the straight line 2x + 3Y = 0, that is, the slope is equal, k = - 2 / 3
The intercept on the y-axis is - 3, that is, B = - 3
Substitute y = KX + B to get
y=-2/3x-3

The simple method of solving 13 / (x-4) - 10 / (x-3) = 4 / (X-5) - 1 / (x-1) 1 / (x + 1) + 1 / (x + 7) = 1 / (x + 5) + 1 / (x + 3) is simpler

13/(x-4)-10/(x-3)=4/(x-5)-1/(x-1)
The left and right sides are divided
（3x+1)/(x-4)(x-3)=(3x+1)/(x-5)(x-1)
Ψ 3x + 1 = 0 or (x-4) (x-3) = (X-5) (x-1)
Ψ x = - 1 / 3 or x = 7
1/(x+1)+1/(x+7)=1/(x+5)+1/(x+3)
2(x+4)/(x²+8x+7)=2(x+4)/(x²+8x+8)
X + 4 = 0 or X & sup2; + 8x + 7 = x & sup2; + 8x + 8 (nonsense)
x=-4

Given that the line y = KX + B is parallel to y = 3x and intersects with y = 1 / 2x + 2 at a point on the y-axis, then k =, B = the analytical formula of the line
Given that the line y = KX + B is parallel to y = 3x and intersects with y = 1 / 2x + 2 at a point on the y-axis, then k =, B = the analytical formula of the line

Remember, two parallel lines mean K is equal, so the unknown line k = 3
Let's see that the intersection of y = 1 / 2x + 2 and Y axis is x = 0, and then we get the point (0.2)
This point is also a point on the unknown line, so (0,2) is substituted into the unknown line
We get 2 = B
So k = 3, B = 2
The analytic formula is y = 3x + 2

If the real numbers a, B and C are in equal proportion sequence, then the number of intersections between the image and x-axis of the function f (x) = AX2 + BX + C is

Real numbers a, B and C are in equal proportion sequence, B ^ 2 = AC > 0, Δ = B ^ 2-4ac = ac-4ac = - 3aC

It takes 2.56s for the transmitted radio wave to reach the moon and return to the ground. The propagation speed of the radio wave is 3 times the octave M / s of ten. The distance from the moon to the ground

x=ct/2=3*10^8*2.56/2=3.84*10^8m
The distance from the moon to the ground is 3.84 * 10 ^ 8m