Solution equation: 2 (x + 20) = 3x-38

2x+40=3x-38
3x-2x=40+38
x=78

X-8 / 3x + 20 = 45 X - (30 + 50) = 7 / 5x solve the equation!

3x + 20 = 45
5/8x=25
x=40
X - (30 + 50) = 5x out of 7
x-5/7x=80
2/7x=80
x=280

Solving equation (3x-2) * (3x-2) - (2 + 3x) = 20
Factorization

（3X-2）*（3X-2）-（2+3X）=20
（3X-2）^2-3x-2=20
（3X-2）^2-3x=22
（3X-2）^2-(3x-2)=24
（3X-2）^2-(3x-2)+1/4=24+1/4
[(3x-2)^2-1/2]^2=97/4
(3x-2) - 1 / 2 = ± 97 / 2 under root
X = (97 + 5 under radical) / 6
Or x = (97 under 5-radical) / 6
（3X-2）*（3X-2）-（2+3X）=20
9x^2-12x+4-2-3x=20
9x^2-15x=18
(3x)^2-15x+(5/2)^2=18+25/4
(3x-5/2)^2=97/4
3x-5 / 2 = ± 97 / 2 under root
X = (97 + 5 under radical) / 6
Or x = (97 under 5-radical) / 6

2 / 3x-20% x = 1

2/3X－20%X=1
2/3x-1/5x=1
10x-3x=15
7x=15
x=15/7

Let f (x) = x2-2x + 2, the minimum value of X ∈ [T, t + 1] (t ∈ R) be g (T), and find the expression of G (T)

F (x) = x2-2x + 2 = (x-1) 2 + 1, so the symmetry axis of the image is a straight line x = 1, and the opening of the image is upward

What is the derivative of the function f (x) = 3sinx + cosx?
Help me. It's easy

f'（x）=3cosx-sinx

1. The cost of a day's work for Party A and Party B is 10000 yuan and 10000 yuan respectively. For a project, if the two teams cooperate, it can be completed in 12 days, and 480000 yuan needs to be paid to the two teams. Now, team a sits alone for five days, and then team a and Party B cooperate for four days. As a result, only the general cost of the whole project is completed. At this time, the project cost of the two teams is 235000 yuan
(1) How many days does it take for team a and team B to complete the project separately?
(2) If the project management department decides to choose one of the two teams to complete the project independently, which one should be chosen from the perspective of saving money?
Another question:
A classmate plans to walk 30 kilometers to visit the museum. Due to the change of circumstances, he should ride a bicycle, and the speed of the car is 1.5 times that of the walking speed, so that he can arrive two hours ahead of schedule. How fast does the classmate ride a bicycle?

1. (1) the number of days a needs to work alone is 5 / (1 / 2-4 / 12) = 30 days, and the number of days B needs to work alone is 1 / (1 / 12-1 / 30) = 20 days. (2) the daily engineering cost of Party A is (23.5-48 * 4 / 12) / 5 = 15000 yuan, the cost of Party A to complete the project alone is 1.5 * 30 = 450000 yuan, and the daily engineering cost of Party B is (23.5-48 * 4 / 12) / 5 = 450000 yuan

General solution of Y '' = e ^ 2Y differential equation
The one above has already met
XY '' = y '(LNY' - LNX) for general solution!!!!!!!!!!! Thank you very much!!!!!!!!!

xy''=y'(lny'-lnx)
y''=y'/x(lny'/x)
y'/x=u y'=xu y''=u+xu'
u+xu'=ulnu
xu'=ulnu-u
du/(ulnu-u)=dx/x
ln(lnu-1)=lnx+lnC1
lnu-1=C1x
u=e^(C1x+1)
y'=xe^(C1x+1)
Just integral

How to write the English letter of 40

forty

123456789 = 81 fill in + or - in the appropriate position to make the formula true

1 2-3+4+5-6+7 8-9=81

Solution equation: 2 (x + 20) = 3x-38