First order inequality equation of one variable! Solving expert solution! Speed! Online waiting ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ process!) If you ask the photography department to take a picture, you will have to pay 5.60 yuan (including 2 photos). If you print another photo, you will have to pay 0.48 yuan. If you pay no more than 1 yuan, and you can get one photo, how many students are there at least?

First order inequality equation of one variable! Solving expert solution! Speed! Online waiting ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ process!) If you ask the photography department to take a picture, you will have to pay 5.60 yuan (including 2 photos). If you print another photo, you will have to pay 0.48 yuan. If you pay no more than 1 yuan, and you can get one photo, how many students are there at least?

If you have X students, you can get 5.6 + 0.48 (X-2) less than or equal to x, you can get x greater than or equal to 8.9, but people are one by one, they have no half life, so they are 9

Solving the equation 2x + 36x + 1 = 0

2X square?
If so, the solution is
x①=-0.027820777536819108
x②=-17.972179222463182

Given that there are exactly three integers in the set a = {x | a ＜ = x ＜ = 2-A} (a ＜ 1), the value range of real number a is
Given that there are exactly three integers in the set a = {x | a ＜ = x ＜ = 2-A} (a ＜ 1), the value range of real number a is

It is known that there are exactly three integers in the set a = {x | a ＜ = x ＜ = 2-A} (a ＜ 1)
Then a + 3

Why is 4x's square-7xy's square + 3x-14 a quintic trinomial, and its quadratic term is 4x's Square. What's the constant term
If it's not a quintic trinomial, how much is it? Is its quadratic term the square of 4x

4X ^ 2-7xy ^ 2 + 3x-14 is a cubic binomial
Because the degree of a polynomial is the degree of the item with the highest degree in the polynomial,
In this polynomial, 4x ^ 2 is degree 2, - 7xy ^ 2 is degree 3, + 3x is degree 1, and - 14 is a constant term, which is specified as degree 0,
So this polynomial is not a quintic trinomial!
Its quadratic term is 4x ^ 2 and its constant term is - 14

If f (x) = cosxex & nbsp;, then the tangent equation of F (x) at point (0, f (0)) is ()
A. x-y+1=0B. x+y-1=0C. cos•x+y-1=0D. ex •x+cosx•y+1＝0

∵ f (x) = cosxex & nbsp;, ∵ f ′ (x) = - E-X (SiNx + cosx), ∵ f ′ (0) = - 1, ∵ f (0) = 1, ∵ the tangent equation of the image of function f (x) at point a (0,1) is Y-1 = - 1 × (x-0), that is, x + Y-1 = 0, so B is selected

In three fifths, there are () quarters, and one sixth is () times of two fifths

Twelve out of five

If the dial of the meter turns 500 revolutions in 10 minutes, the electric energy consumed by the circuit is
(just do the second question)
(1) please write down the meaning of the relevant numbers on the dial. ① 02860:; ② 220V:; Ⅷ 5A:; ④ 10A:; ⑤ 2500r / kW? H: (2) if the dial of the meter turns 500 revolutions in 10 minutes, the electric energy consumed by the circuit is kWh

2500r / kW. H means that 2500 turns is one degree of electricity
500 / 2500 = 0.2 degree = 0.2kwh
Unknown can be questioned

Set a = "x / x square + 4x = 0" B = "x / x square + 2 (a + 1) + a square - 1 = 0" if B belongs to a, find the value range of real number a
fast

A x^2+4x=0
x=0,x=-4
B x^2+2(a+1)x+a^2-1=0
B belongs to a
There are three situations
(1) B is an empty set
Then the equation has no real solution
Discriminant = 4 (a + 1) ^ 2-4 (a ^ 2-1) = 4A ^ 2 + 8A + 4-4a ^ 2 + 4 = 8A + 8

Calculation formula of motor power
Calculation of motor power formula motor power P = Fv / 1000 η (this is in the manual), but recently I saw this formula P = (1.1.5) Fv / 102 η 1 * η 2 (I remember seeing this formula when I was in school, but I don't know where it is now). Are these two formulas spear shield? And when can I calculate power without considering the moment of inertia

P=W/t =UI
In the pure resistance circuit, according to Ohm's law, u = IR can be substituted into P = UI to get P = I2R = (U2) / R

General score: (1) A-2 / A-3, a + 1 / - (A-2) (3-A) (2) x / a (X-Y), Y / b (Y-X)
Hope to be more detailed

-(a-2)(3-a)=(a-2)(a-3)
So (A-2) / (A-3) = (A-2) ^ 2 / (A-2) (A-3)
(a+1)/-(a-2)(3-a)=(a+1)/(a-2)(a-3)
y-x=-(x-y)
Cm mother AB (X-Y)
x/a(x-y)=bc/ab(x-y)
y/b(y-x)=-ax/ab(x-y)