If 2x + 5 and 9-3X are opposite numbers, then the value of X-2 is______ .

If 2x + 5 and 9-3X are opposite numbers, then the value of X-2 is______ .

According to the meaning of the question, we can get: (2x + 5) + (9-3X) = 0, the solution is: x = 14, substituting x = 14 into X-2, we can get: X-2 = 14-2 = 12
1. Given that 3x + 6 and 2x + 9 are opposite numbers, try to find the value of X
2. On the number axis, the number represented by point a is - 2.5, the number represented by B and C are opposite to each other, and the distance from point B to point ade is 3, then the number represented by point C is ()
1. (3x + 6) + (2x + 9) = 05x + 15 = 0x = - 32, point B can be expressed as - 5.5, then point C can be expressed as 5.5, point B can be expressed as 0.5, then point C is expressed as - 0.5, very happy to answer for you, I wish you progress in your study! Always 523 for you to answer ~ ~ if you agree with my answer, please click the following [select as satisfied
﹙1﹚3x＋6＋2x＋9＝0
5x＝﹣15
x＝﹣3.
(2) if B = 3-2.5 = 0.5, then the number represented by point C is - 0.5;
② B = - 2.5-3 = - 5.5, then the number represented by point C is 5.5
If - 2x + 5 and - 9 + 3x are opposite numbers, then the value of X-2 is
Because they are opposite numbers
So they add up to 0
So - 2x + 5 = - 9 + 3x
The solution is x = 5 / 14
x-2=-23/14
Given that x + Y-1 and X + 2 are opposite numbers, and a and B are reciprocal, find the value of XY + ab
｜x+y-1｜+｜x+2｜=0
x+y-1=0,x+2=0
x=-2,y=3
ab=1
So XY + AB = - 6 + 1 = - 5
Expression of mathematical letter formula
Cylindrical: letter formula of surface area: letter formula of height of radius
Volume letter formula: bottom height
High radius
Diameter height
Please write the letter formula for these,
Hello
The radius is R and the height is h
The area of the bottom of the cylinder = π R & # 178;
Cylinder side area = 2 π RH
Surface area of cylinder = 2 π R & # 178; + 2 π RH
Cylinder volume = π R & # 178; H
If you don't understand, please ask. If you understand, please select it as a satisfactory answer in time! (*^__ ^*Thank you!
S=2 π r h
V=S h
V = π (R) square H
V = π (D / 2) square H
Surface area of cylinder: 2 π R ^ 2 + 2 π Rh (area of two bottom surfaces + side area)
Cylinder volume: bottom height: SH
Radius height: π R ^ 2H
π（d/2）^2h
Both denote the bottom area X, h is the height, R is the bottom radius, D is the bottom diameter, s is the bottom area
The surface area s is equal to π R & # 178; + 2 π RH. V equals π R & # 178; H
S=2 π r h
V=S h
V=π (r)^2 h
V=π （d/2）^2h
Unfolding the cylinder is a rectangular piece of paper and two circles of the same size. The surface area formula of rectangle is length * width. The circumference of the base of a cylinder is similar to the length of a rectangle, and the height is similar to the width. The formula of the circumference of the bottom surface of the cylinder is 2 π r = π D, the formula of the area of the bottom surface is π R & # 178; = π (D / 2) &# 178;, so the formula of the surface area of the cylinder is 2 π RH + 2 π R & # 178;
The volume of a cylinder can be regarded as the volume occupied by the superposition of numerous circles, so the volume of a cylinder can be obtained by multiplying the area of the bottom by the height.
The area of the bottom is expanded
Unfolding the cylinder is a rectangular piece of paper and two circles of the same size. The surface area formula of rectangle is length * width. The circumference of the base of a cylinder is similar to the length of a rectangle, and the height is similar to the width. The formula of the circumference of the bottom surface of the cylinder is 2 π r = π D, the formula of the area of the bottom surface is π R & # 178; = π (D / 2) &# 178;, so the formula of the surface area of the cylinder is 2 π RH + 2 π R & # 178;
The volume of a cylinder can be regarded as the volume occupied by the superposition of numerous circles, so the volume of a cylinder can be obtained by multiplying the area of the bottom by the height.
The formula of bottom area = π R & # 178; = π (D / 2) & # 178;, volume = bottom area * height = π R & # 178; H = π (D / 2) & # 178; H
R is the radius, D is the diameter, h is the height
Find the natural number solution of inequality system 3x - 6 ＜ 4 - XX - 1 ＞ 4x - 10
If we solve the inequality 3x-6 ＜ 4-x to get: X ＜ 52, and solve the inequality X-1 ＞ 4x-10 to get: X ＜ 3, then the solution set of the inequality system is: X ＜ 52, so the natural number solutions of the inequality system 3x-6 ＜ 4-xx-1 ＞ 4x-10 are 0, 1, 2
The relationship between quadratic function image and ABC. For example, when a decides the opening direction and AB has the same sign, which side of the y-axis is the image, and C decides what. Just give me these relationships. Don't have too many knowledge points
a> 0 opening up; a
a> 0, opening upward; a
It is known that the maximum value of the function f (x) = - 2x2 + 3Tx + T (x, t ∈ R) is u (T). When u (T) has a minimum value, the value of T is ()
A. 94B. −94C. 49D. −49
F (x) = - 2x2 + 3Tx + T = − 2 (x − 3t4) 2 + 98t2 + T, the opening of parabola is downward, when x = 3t4, f (x) gets the maximum value 98t2 + T, that is, u (T) = 98t2 + T, ∵ U (t) = 98t2 + T = 98 (T2 + 89t) = 98 (T + 49) 2 − 29, ∵ t ∈ R, ∵ when t = − 49, u (T) has the minimum value - 29
{y-2x/xy=5,5y+7x/xy=22}
I.e. 1 / X-2 / y = 5 (1)
5/x+7/y=22 (2)
(1)*7+(2)*2
16/x=79
1/x=79/16
1/y=(1/x-5)/2=-1/32
So x = 16 / 79, y = - 32
First reduce the order, Y / xy-2x / xy = 5, get 1 / X-2 / y = 5, then multiply both sides by XY, get y-2x = 5xy;
Similarly, 5Y / XY + 7x / xy = 22, get 5 / x + 7 / y = 22, multiply both sides by XY, get 5Y + 7x = 22xy;
Then, using the elimination method, multiply Formula 1 by - 22 / 5 to get (- 22 / 5) y + 22xy + (44 / 5) x = 0, then use this formula to add 5Y + 7x = 22xy (remember to move the term to the right of the equal sign), and then calculate y = (- 79 / 3) x
First reduce the order, Y / xy-2x / xy = 5, get 1 / X-2 / y = 5, then multiply both sides by XY, get y-2x = 5xy;
Similarly, 5Y / XY + 7x / xy = 22, get 5 / x + 7 / y = 22, multiply both sides by XY, get 5Y + 7x = 22xy;
Then use the elimination method, multiply Formula 1 by - 22 / 5 to get (- 22 / 5) y + 22xy + (44 / 5) x = 0, then use this formula to add 5Y + 7x = 22xy (remember to move the term to the right of the equal sign), then calculate y = (- 79 / 3) x, bring in Formula 1, eliminate y, then you can calculate the root of X, and then bring in the root of X to solve the value of Y. Put it away
Do chemical expressions refer to Chinese characters or letters
The chemical expression of letters is simply to express reactions, that is, chemical equations are written without equal sign, arrows are written without balance, and words are written expressions