An applied problem of inequality in the first grade of junior high school The fruit shop bought one ton of certain fruit at the price of 7 yuan per kilogram and sold it at 11 yuan per kilogram. In order to sell out as soon as possible after half of the sale, it is ready to sell at a discount. If the total profit is not less than 3450 yuan, then the remaining fruit should be sold at least at a discount of the original price? Use inequality or one yuan linear equations to solve the problem

An applied problem of inequality in the first grade of junior high school The fruit shop bought one ton of certain fruit at the price of 7 yuan per kilogram and sold it at 11 yuan per kilogram. In order to sell out as soon as possible after half of the sale, it is ready to sell at a discount. If the total profit is not less than 3450 yuan, then the remaining fruit should be sold at least at a discount of the original price? Use inequality or one yuan linear equations to solve the problem

If the profit of half sold is (11-7) multiplied by 500, it will be 2000. Then the profit of the remaining half will be at least (3450-2000), 1450, and then divided by 500, it will be 2.9. That is to say, the price of the remaining half per kilogram is (7 + 2.9), equal to 9.9. Finally, 9.9 divided by 11, it will be 0.9, that is, it will be sold at least 10% off the original price

An applied problem of inequality in the first grade of junior high school
There are 1530 tons of class a goods and 1150 tons of class B goods in a storage and transportation station. A freight car is arranged to transport the goods to the destination. The freight car can carry 50 sections of a and B freight cars. It is known that 35 tons of class a goods and 15 tons of class B goods can fill a section of type a freight car, 25 tons of class a goods and 35 tons of class B goods can fill a section of type B freight car, What kind of transportation plan do you have? Please design it

（1）y=0.5x+0.8(50-x)
It is reduced to y = 40-1.3x
(2) If X type a cars are needed, then (50-x) type B cars are needed,
List the inequality groups
15x + 35 (50-x) greater than or equal to 1150
35x + 25 (50-x) greater than or equal to 1530
The solution is 28 less than or equal to x less than or equal to 30
Because x is an integer, x = 28,29,30
So three schemes are used
There are 28 type a cars and 22 type B cars;
There are 29 type a cars and 21 type B cars;
There are 30 type a cars and 20 type B cars;

A math problem (application problem)
A man bought 100 animals for 100 yuan, a dog for 10 yuan, a cat for 3 yuan and a mouse for 50 Fen. How many animals did he buy?

Suppose there are x dogs, y cats and Z mice
So x + y + Z = 100
10x+3y+0.5z=100
x. Y and Z are integers
The solution is x = 5, y = 1, z = 94
There are five dogs, one cat and 94 mice

Given that the vertex of the parabola y = x2 + (m-1) X-1 / 4 is on the Y axis, then the value of M is?

The vertex of the parabola y = x & # 178; + (m-1) X-1 / 4 is on the Y axis,
∴m-1=0
m=1

10000 × (1 x) 2 = 12100 calculation process

10000 × (1 + x) & # 178; = 12100 both sides divide by 10000 at the same time
(1+x)²=1.21
1+x=±1.1
x=-1±1.1
x1=0.1,x2=-2.1

How to use auxiliary angle formula to simplify - √ 3 / 2sinx + 1 / 2cosx
According to the auxiliary angle formula, a ^ 2 + B ^ 2 under the root sign should be 1, θ should be - π / 6, and the answer should be sin (X-6 / π); but in fact, it should be sin (6 / π - θ). Why?

Your formula is not very good, sin (X-Y) = sin (x + (- y)) = sinxcos (- y) + cosxsin (- y), SiNx is odd function, cosx is even function, so
Cos (- y) = cosy, sin (- y) = - siny, so sin (X-Y) = sinxcosy cosxsiny
-Cos (π / 6) SiNx + sin (π / 6) cosx = sin (π / 6) cosx cos (π / 6) SiNx
In addition, according to what you said, cos θ = - 3 / 2, sin θ = 1 / 2, θ should be 5 π / 6 + 2K π, and the sine of - π / 6 is - 1 / 2, not 1 / 2

(x+y)(x+y+2xy)+(xy+1)(xy-1)
(x+y)(x-y)+4(y-1)

(x+y)(x+y+2xy)+(xy+1)(xy-1)=(x+y)^2+2xy(x+y)+(xy)^2-1=(x+y+xy)^2-1=(x+y+xy+1)(x+y+xy-1)(x+y)(x-y)+4(y-1)=x^2-y^2+4y-4=x^2-(y^2-4y+4)=x^2-(y-2)^2=(x+y-2)(x-y+2)

For quadratic function y = 2x ^ 2-3x + 5, when y > 0, the value range of X is?
There are two situations!

y=2(x-3/4)^2-9/8+5=2(x-3/4)^2+31/8>0
Value range R

The axis of symmetry of parabola y = 3x (the square of x) - x is x = - 1 / 6, right or wrong

Substituting the formula of symmetry axis X = B / - 2A, a = 3. B = - 1,
X = 1 / 6, wrong

If the parabola y = x & # 178; + BX + C has only one intersection with the X axis and passes through points a (m, n), B (M + 4, n), then n =?

∵ parabola y = x & # 178; + BX + C passing through points a (m, n), B (M + 4, n), ∵,
The axis of symmetry is x = m + 2
The parabola y = x & # 178; + BX + C has only one intersection with the X axis,
Let the analytic formula of parabola be y = (x-m-2) &# 178;,
By substituting a (m, n), we get
N = (m-m-2) ² = 4, i.e. n = 4
So the answer is: 4