If the value of the algebraic expression 3x − 12 is between - 1 and 2, the integer that x can take is () A. 1 B. 2 C. 3 d. 4

If the value of the algebraic expression 3x − 12 is between - 1 and 2, the integer that x can take is () A. 1 B. 2 C. 3 d. 4

We can get 3x − 12 ＞− 13X − 12 ＜ 2 from the meaning of the question, and we can get x ＜ 53 from (1) x ＞ - 13 and (2), so the solution set of the inequality system is - 13 ＜ x ＜ 53, then x can take two integers of 0 and 1

What is the value of X? The value of algebraic formula 2 (x-3) is equal to that of 1-3x

2(x-3)=1-3x
2x-6=1-3x
5x=7
x=7/5

If the solutions of the equations 2x + 5Y = 4 and 5x + 2Y = 2m-3 satisfy the equation x + y = 1 / 7, then the value of M is?
If the answer comes out, increase the reward

2x+5y=4 …… ①
5x+2y=2m-3…… ②
① + 2, get it
7x+7y=2m+1
Then x + y = (2m + 1) / 7
∵x+y=1/7
∴2m+1=1
2m=0
m=0
The answer is not 3, but 0

After a piece of paper is cut, it is made into a rectangle with the same radius and area. The circumference of the rectangle is 33.12cm

Radius 33.12 △ 2 △ 3.14 + 1 = 16.56 △ 4.14 = 4cm
Area: 3.14 × 4 × 4 = 50.24 square centimeter

Given that the first n terms and Sn of sequence {an} satisfy log2 (Sn + 1) = n + 1, the general term formula of sequence {an} is obtained

From the known Sn + 1 = 2N-1, we get Sn = 2n + 1-1, so when n = 1, A1 = S1 = 3; when n ≥ 2, an = sn-sn-1 = 2n, and A1 = 3 does not conform to an = 2n, so the answer is an = 3 (n = 1) 2n (n ≥ 2)

The cost of a taxi in a certain area is calculated as follows: the starting price is 9 yuan within 3000 meters, and 2 yuan for every additional kilometer
Someone paid 19 yuan when he arrived at the terminal. Suppose that the taxi just drove the whole kilometer, how many kilometers did the taxi drive?

You can deduct the money for the first 3000 meters, that is, 19-9 = 10 yuan, and pay 2 yuan for every additional kilometer you drive in the future, 10 △ 2 = 5 km. This step is to walk several thousand meters after 3000 meters, 5 km plus 3 km in front, which is 8 km
A: the taxi drove 8 kilometers
Very happy to answer for you! Please accept!

As shown in the figure, in the pyramid p-abcd, the bottom surface ABCD is rectangular, PA ⊥ plane ABCD, m and N are the midpoint of AB and PC respectively, PA = ad = A. (1) verification: Mn ∥ plane pad; (2) verification: plane PMC ⊥ plane PCD

It is proved that: (1) let the midpoint of PD be e, connecting AE and NE, and let n be the midpoint of PC, then we know en ‖. 12DC, and ABCD be a rectangle, then ABCD is a rectangle, then ABCD is a DC, then AB, then M is the midpoint of AB, then am and amne are parallelograms, and AE ⊂ planar pad, nm ⊄ planar pad, then Mn ‖ planar pad

The negative power of a number
For example, what is the - 1 power of 2 equal to

Equal to the reciprocal of the power of this number
For example, the - 1 power of 2 equals the reciprocal of 2, which is 1 / 2

-2^99*(-1\2)^100+8^101*(-0.125^100)

（-2*-1/2）^99*-1/2-(8*0.125)^100*8
=-0.5-8=-8.5

As shown in the figure, ∠ B = ∠ C = 90 °, M is the midpoint of BC side, am bisects ∠ DAB, and verification: DM bisects ∠ ADC
I hope it can be written in the form of proof
Reply within one day

However, it is not easy for him to use the congruent method. I offer a second method
Method 2
Make me ⊥ ad
Then me and MB are the distance from m point on the bisector am to both sides
Ψ me = MB (the distance from one point on the bisector to both sides is equal)
Similarly: me and MC are the distance from m point to both sides of DM line
∵ m is the midpoint of BC side
∴MB=MC
∴ME=MC
Ψ DM is the angular bisector of ∠ ADC, that is, DM bisectors ∠ ADC