In the following formula, whose result is the closest to half? A: two thirds plus three quarters B: seven out of nine minus five out of nine C: five out of eight minus four

In the following formula, whose result is the closest to half? A: two thirds plus three quarters B: seven out of nine minus five out of nine C: five out of eight minus four

A=17/12 B=2/9 C=?
Subtract 1 / 2 from ABC to see who is the smallest\
The title is not complete, can't see a quarter of C?

The solution of the system of equations 2x + y = 3K-1 x + 2Y = - 200 of XY satisfies x + Y > k for a
The solution of the system of equations 2x + y = 3K-1 x + 2Y = - 200 satisfies the value range of X + Y > k for a

2x+y=3k-1 (1)
x+2y=-2 (2)
From (1) * 2 - (2)
3x=6k-2+2
x=2k
Substitute (1) to get
y=3k-1-4k=-k-1
Since x > 3, y ≤ - 3, then
2k>3 -k-1≤-3
k>3/2 k≥2
∴ k≥2

Use the properties of the equation to solve the following equation 12-x = 3x + 8 for 3 minutes

12-X=3x+8
12-x+x-8=3x+8+x-8
4x=4
x=1

X + 5 / 9 = 2
x=

2 equals 18 out of 9, and then subtract 5 out of 9 to get x = 13 out of 9

Party A and Party B respectively travel from AB, 65km / h for Party A and 60km / h for Party B. the two cars meet at 15km away from China. How many km do you want to be away from ab?

Meet at 15km from the midpoint
Jiaduo walked 15 * 2 = 30km
Time 30 / (65-60) = 30 / 5 = 6 hours
Distance (65 + 60) * 6 = 125 * 6 = 750km

Calculation: 20032003 × 2003-20032002 × 2002-20032002=______ ．

20032003 × 2003-20032002 × 2002-20032002 = 20032003 × 2003-20032002 × (2002 + 1) = 20032003 × 2003-20032002 × 2003 = 2003 × (20032003-20032002) = 2003 × 1 = 2003

One yuan per time, a and B trains leave each other at two stations 120 kilometers away. A's speed is 84 km / h, B's speed is 60 km / h, so it's a good choice
The two trains a and B leave each other at two stations 120 km apart. The speed of a is 84 km / h, and that of B is 60 km / h. how long does it take for the two trains to be 24 km apart?

The distance between the two vehicles is 24 km after passing x hours
I didn't meet you
　∴(84+60)x=120-24
　　144x=96
　　x=2/3
We have met
　∴(84+60)x=120+24
　　144x=144
　　x=1
A: after 2 / 3 hours, or after 1 hour, the distance between the two cars is 24 kilometers

7 and 1 / 5 / 0.24-2 and 2 / 7 * 0.875 =? Important process

7 and 1 / 5 / 0.24-2 and 2 / 7 * 0.875
=36/5x25/6-15/7x7/8
=30-15/8
=28 and 1 / 8

Huaian city is 120 kilometers away from Lianyungang. Two cars run from each other at the same time and meet in four-thirds of an hour. The speed ratio of the two cars is 4:5
How many kilometers per hour do the two cars travel?

120 △ 4 / 3 = 90 (km) (sum of the speeds of a and B vehicles)
90 (1 + 4 / 5) = 50 (km) B vehicle speed
90-50 = 40 (km) a vehicle speed

If you move the decimal point one place to the left, it will be 2.88 less than the original number______ ．

According to the meaning of the question: 2.88 △ 10-1 = 0.32; 0.32 × 10 = 3.2