A and B run on a 400 meter long circular track. It is known that a runs 9 meters per second and B runs 7 meters per second How many seconds did it take for two people to meet for the first time when they were walking in the same direction at the same time?

A and B run on a 400 meter long circular track. It is known that a runs 9 meters per second and B runs 7 meters per second How many seconds did it take for two people to meet for the first time when they were walking in the same direction at the same time?

Set X seconds later
In the same direction, 9x-7x = 400
x=200
That is to say, after starting at the same time, a runs fast, and then sets a lap for B. therefore, multiplying their speed difference by time should be 400 meters per lap

Is X-1 / x = 1 a linear equation with one variable?

Simply tell you, there are unknowns in the denominator is the fractional equation~
The first-order equation of one variable and fractional equation are different concepts
A linear equation of one variable must be integral

Is x + 8 = x a linear equation with one variable?

No, the shift term x-x = 8,0 x = 8, the coefficient of the first term of the linear equation of one variable cannot be 0

Five times of a number minus five equals four times of the number. What is the number? (solve the equation)
I'm from primary school. Don't say I'm ignorant

5x-5=4x
So x = 5;

A number minus 40% is equal to the product of 6 times 1 / 2

The product of 6 times 1 / 2 = 3
A number minus 40% = 60% of the number
This number = 3 △ 60%
This number = 5

3 times of a number minus 8.1 is the product of 2.9 and 3. What is the number
3 times of a number minus 8.1 is the product of 2.9 and 3. What is the number

Let this number be X
3X-8.1=2.9*3
X=5.6

The product of 4.6 minus 2 and 0.4 is less than 3 times of X by 0.1, so we can find the number of X
Three 15x - (5x + 7) (when x = 12)
5aa + BC (when a = 5, B + 1.2, C + 2.5)
4 9.6-0.4x = 2.81.1 (4x-2) = 12.13 (8 + x) △ 2 = 18
(calculated by equation)

The product of 4.6 minus 2 and 0.4 is 0.1 less than 3 times of X, so we can find X
4.6-2×0.4=3x-0.1
3x=3.9
x=1.3
Four times of two plus three equals five times minus two
(3+2)÷（5-4）=5
Three 15x - (5x + 7)
=15x-5x-7
=10x-7
=10×12-7
=120-7
=113 (when x = 12)
5aa+bc
=5*5*5+1.2*2.5
=125+3
=128 (when a = 5, B = 1.2, C = 2.5)
4 9.6-0.4x = 2.8
0.4x=9.6-2.8
0.4x=6.8
x=17
1.1(4x-2)=12.1
4x-2=11
4x=13
x=13/4
3(8+x)÷2=18
3(8+x)=36
8+x=12
x=4
(calculated by equation)

The product of two numbers is 286. If you subtract 3 from one of the factors, the product will be 220?

If one is x and the other is 286 / x, then (x-3) * (286 / x) = 220, and the solution is x = 13, then one is 13 and the other is 22

The product of 4 times the sum of a number and 5 is equal to 60. What is the quotient of 1 minus 0.19 divided by the sum of 0.3 and 0.6?
Solving equations for two problems

(1) 60÷4=5=10
(2) (1-0.19)÷0.9=0.9

2.4 times of a number minus half of the number equals 38, and what is the sum?

The number is 2.4-0.5 = 1.9
38÷1.9=20
And: (2.4 + 0.5) × 20 = 2.9 × 20 = 58