3x+2y+z=4 x+y+z=10 2x+3y-z=1

3x+2y+z=4 x+y+z=10 2x+3y-z=1

1）3x+2y+z=4
2）x+y+z=10
3）2x+3y-z=1
1) Add 3), 5x + 5Y = 5
2) Add 3), 3x + 4Y = 11
x=-7
y=8
z=9

x+y-z=6,x+3y+2x=1,3x+2y-z=4
Sorry for solving linear equation of three variables
The second equation is x + 3Y + 2Z = 1

The title should be x + Y-Z = 6 (1)
x+3y+2z=1 (2)
3x+2y-z=4 (3)
(1)-(2)
x+y-z-x-3y-2z=6-1
-2y-3z=5 (4)
(1)*3-(3)
3x+3y-3z-3x-2y+z=18-4
y-2z=14 (5)
(5)*2+(4)
2y-4z-2y-3z=28+5
-7z=33
z=-33/7
y=32/7
x=-23/7

The ratio of team a and team B is 8 to 7. If 8 people are transferred from team a to team B, the ratio of team a and team B is 4 to 5. How many people are there in team a and team B

8/(8+7)-4/(4+5)=4/45
8 △ 4 / 45 = 90 people
A: 90 (8 + 7) × 8 = 48 persons
B: 90-48 = 42

How many three digit numbers can be made up of numbers 0, 1, 2, 3, 4 or natural numbers less than 1000

First of all, you need to know whether these numbers can be reused
If you can, there are 4 × 5 × 5 = 100 species, 4 selection methods for 100, 5 for 10 and 5 for individual
If it can't be repeated, there are 4 × 4 × 3 = 48 species

If the speed of a car is increased from place a to place B, it can arrive one hour earlier than the original time; if it runs 120 km at the original speed, it can arrive again
If you increase the speed, you can arrive 40 minutes earlier. How many kilometers are there between a and B?

60 / (60-40) = 3 3x120 = 360 km

BD and CE are the two heights of acute angle △ ABC respectively. Try to show that points e, B, C and D are on the same circle and draw this circle
I want ideas~

Take the midpoint o of BC and connect do and EO,
∵BD⊥AC,CE⊥AB
∴DO=BC/2,EO=BC/2
∴DO=EO=BO=CO
E, B, C and D are on the same circle

Two cars can transport 60 tons of goods a day, and three cars can transport goods in five days. How many days

Two cars can carry 60 tons of goods a day
Therefore, a car can transport 60 △ 2 = 30 tons of goods a day
Three cars can transport 30 × 3 × 5 = 450 tons in five days

If the real numbers a, B and C satisfy a ^ 2-4b = 8, B ^ 2-6c = - 14, C ^ 2-8a = - 23, then (a-b) ^ C=

And we're going to be in the state of-4b = 8 (1) B and we're going to be 8 (1) B; (; (6c = -14 (2) C and we're going to be; (8a = -14 (2) C and we are going to be (23 (3) (3) (3) (3) (3) (3) (3 (3) (3) (3) (3) (3) (3) (3) (3) (3) (3) (3) a and we are going to be (8 (1) B (1) B (1) b) B; (; (8) C = 8; (6c = -14 (14 (14 (2) C (2) C (2) C; (8) C; (; (; (; (8) C = -14 (14 (14) (2) C; (2) C; (8) C; (8) and we will be 178; (8; (8; (; (8; (8; (8) 8; (8 (8) 8) 8; (8; (8; (8 (8) 8 (8) and the) - 8A; (8a; (8) and+ (C-3) & # 178; = 0 square term, constant nonnegative, triple nonnegative

A batch of goods is to be transported to a certain place, and the owner is going to rent two kinds of trucks from the automobile transportation company
It is known that in the past two times, the number of these two kinds of goods vehicles rented is as follows: the number of type a goods vehicles for the first time is 2, and that for the second time is 5; the number of type B goods vehicles for the first time is 3, and that for the second time is 6; the accumulated tonnage of goods transported for the first time is 15.5 tons, and that for the second time is 35 tons. This time, we need to rent 3 type a goods vehicles and 5 type B goods vehicles of the company. If we just transport these goods to a certain place, we will pay 30 yuan per ton, How much is the freight of this batch of goods? It's two yuan per shipment

Let a transport x tons and B transport y tons
2x + 3y = 15.5
5x + 6y = 35
x = 4
y = 2.5
A: the cost per ton is 500 / 4 = 125 yuan
B: the cost per ton is 300 / 2.5 = 120 yuan
B is more cost-effective
20 * 120 = 2400 yuan

The polar coordinate equation mpcos square O + 3psin square o

The polar coordinate equation mpcos square O + 3psin square o-6coso = 0 is transformed into rectangular coordinate equation
y=psinθ,x=pcosθ
Multiply P on both sides of the polar coordinate equation to get m (PCOS θ) &# 178; + 3 (PSIN θ) &# 178; - 6 (PCOS θ) = 0
x. Y is substituted into MX & # 178; + 3Y & # 178; - 6x = 0