How to solve the equation that 2.7 plus 4x equals 12.7

How to solve the equation that 2.7 plus 4x equals 12.7

It can be concluded from the meaning of the title
2.7+4X=12.7
4X=12.7-2.7
4X=10
The solution is x = 2.5

2.4 * 5-4x equals 2.4

Hello!
2.4×5-4x=2.4
12-4x=2.4
12-2.4=4x
9.6=4x
x=9.6÷4
x=2.4

Solve the equation (x-2500) [(2900-x) / 50 × 4 + 8] = 5000

( x - 2500 )[ ( 2900 - x ) / 50X4 + 8 ] = 5000-( x - 2500 )( x - 2900 ) /200 + 8( x - 2500 ) = 5000-( x" - 2500x - 2900x + 2900X2500 ) /200 + 8x - 20000 = 5000-( x" - 5400x + 725 0000 ) /200 + 8x - 25...

The fruit shop brought in a batch of fruits. On the first day, they sold 15kg more than 1 / 5 of the total. At this time, the ratio of the fruits sold to the rest is 1:3. How many fruits are there in total
It's still one short:
Kilogram?

15 △ [1 △ (1 + 3) - 1 / 5] = 300 kg

When a batch of parts is processed, the work efficiency ratio of Party A and Party B is 5:4. If Party A and Party B complete half of each, Party A will take 12 hours to complete, and how many hours will Party B complete?

12*5/4=15

----------------------Find the period, frequency, initial phase, maximum and effective value of sinusoidal alternating current
1.i=10sin(100πt-π/6)
2 u=220sin(100π+π/2)

1. i=10sin(100πt-π/6)
Period: 2 π / 100 π = 0.02 sec
Frequency: 100 π / 2 π / = 50 Hz
Initial phase: - π / 6
Maximum: 10 A
Effective value: (10 / radical 2) a
2 u=220sin(100π+π/2)
Period: 2 π / 100 π = 0.02 sec
Frequency: 100 π / 2 π / = 50 Hz
Initial phase: π / 2
Maximum: 220 V
RMS: (220 / root 2) V

Chunyuan primary school 200 teachers and students to the outing, a total of 8 rental cars, just full. Bus limit of 30 people, minibus limit of 20 people
How many cars are there

Method 1: Set x buses
30X+20(8-X)=200
X=4
Cart 4 trolley 4
Method 2: assuming that all buses are buses, then:
(8x30-200) / (30-20) = 4 buses
8-4 = 4 buses
If you have a similar question, you can ask me again. This is a hypothetical code problem in primary school!

Let the square matrix a satisfy the square of a-2a-2e = 0, prove that a and a-2e can be inversed, and find the inverse matrix of a and the inverse matrix of (a-2e)

Because a ^ 2-2a-2e = 0
So a (a-2e) = 2E
That is, (1 / 2) a (a-2e) = E
So a and a-2e can be inversed
And a ^ - 1 = (1 / 2) (a-2e)
(A-2E)^-1 = (1/2)A

Let Z satisfy 1 − Z1 + Z = I, then | 1 + Z | = ()
A. 0B. 1C. 2D. 2

Because 1 − Z1 + Z = I, so 1-z = I + Zi, so z = 1 − I1 + I (1 − I) (1 − I) (1 + I) (1 − I) = 2 I2 = − I, then | 1 + Z | = | 1 − I | = 2, so C is selected

Class 1 of Grade 8 should take a group photo when they go out on holiday. If a color negative costs 0.57 yuan, a developing one costs 0.35 yuan, and each person should book one, and the cost is not more than 0.45 yuan, then there are at least () students taking the group photo?
A. 5B. 6C. 7D. 8

According to the meaning of the question, we can get: 0.57 + 0.35x ≤ 0.45X, the solution is: X ≥ 5.7, at least 6 students take the group photo