The approximate interval of the square half zeros of the function f (x) = 3x + 2?

The approximate interval of the square half zeros of the function f (x) = 3x + 2?

f(x)=3x+4-1/2=3x+3.5=0
x=-7/6
So in (- 2, - 1)

Solve the cubic equation {2x + 3Y + Z = - 15 3x + y + 2Z = - 9 x + 2Y + 3Z = - 12

2x+3y+z=-15 ①
3x+y+2z=-9 ②
x+2y+3z=-12 ③
3 * ① - 2 * ② is 7y-z = - 27 ④
① - 2 * 3 is - y-5z = 9, 5
④ + 7 * ⑤ is - 36z = 36, z = - 1
Substituting Z into 4 gives y = - 4
Substituting y and Z into 1, we get x = - 1
So x = - 1, y = - 4, z = - 1
o(∩_ ∩)o

x-2y+z=9 2x+y+3z=10 3x+2y-z=3

x-2y+z=9 (1)
2x+y+3z=10 (2)
3x+2y-z=3 (3)
(1) 3 - (2)
x-7y=17 (4)
(1) + 3
4x=12
x=3
Substituting (4) to get:
7y=-14
y=-2
Substituting (1) to get:
z=9-3-4
z=2
So: the solution of the equations is: x = 3; y = - 2; Z = 2

The area enclosed by y = x & # 178; and Y & # 178; = x

A=∫(0,1)(√x-x²)dx
=2/3*x^(3/2)-x^3/3|(0,1)
=2/3-1/3
=1

Guangming Middle School has an existing school building area of 20000 square meters. In order to improve the school running conditions, it is planned to demolish some old school buildings and build new school buildings, so that the area of the new school buildings is more than 1000 square meters, which is three times the area of the demolished old school buildings. In this way, the total area of the school buildings after the completion of the plan can increase by 20% compared with the area of the existing school buildings It will cost 700 yuan. How much will it cost to complete the plan?

If the area of the old school building to be demolished is x square meters, then the area of the new school building is 3x + 1000 square meters. According to the meaning of the question: 20000-x + 3x + 1000 = 20000 (1 + 20%), the solution is: x = 1500  3x + 1000 = 5500. The cost to complete the plan is: 80 × 1500 + 5500 × 700 = 3970000 yuan. A: it will cost 3970000 yuan to complete the plan

It is known that the sequence {an} is an equal ratio sequence, and Sn is the sum of its first n terms. Is Sn, s2n Sn, s3n-s2n an equal ratio sequence? Proof

Let the common ratio of the equal ratio sequence {an} be q, then Sn, s2n Sn, s3n-s2n are equal ratio sequence, and the common ratio is Q ^ n. proof: first, a more general formula is proved. In the equal ratio sequence, an = a1q ^ (n-1) am = a1q ^ (m-1) is divided by an / am = q ^ (n-m), 〈 an = AMQ ^ (n-m). S2n = a1 + A2 +... + an + a (n + 1) + a (n +...)

Convert the following percentages to decimals or integers
3%
80％
1.25%

3%=0.03
80％=0.8
1.25%=0.0125

It is known that the cross section of the reservoir dam is trapezoidal ABCD, the dam height is 8m, the slope of slope AB is I = 1:2, and the broken angle of slope CD is 60 degrees

Make 2 verticals as high
So quadrilateral has no rectangle
The last two times were 60
It's going to be similar twice
The answer will come out

How to put a chair in a square empty room and put 10 chairs along the four sides? If we want to make the number of chairs on each side equal, how should we put these 10 chairs? (please draw a diagram)

As shown in the figure:

Given that a is an invertible matrix, what is the relationship between the determinant of a and the invertible determinant of a~

Reversible by a, AA ^ - 1 = E
Take the determinant on both sides to get | AA ^ - 1 | = | E|
That is, there is | a | a ^ - 1 | = 1
So | a ^ - 1 | = | a ^ - 1