The process of solving an equation needs to be written out completely, X-0.8=10-2.8X

The process of solving an equation needs to be written out completely, X-0.8=10-2.8X

X-0.8=10-2.8X
X-0.8+2.8X=10-2.8X+2.8X
(1+2.8)X-0.8=10
3.8X-0.8+0.8=10+0.8
3.8X=10.8
3.8X/3.8=10.8/3.8=108/38=54/19
X=54/19

How to solve this equation
The surface area of the earth is about 2 and 29 parts 13 (13 / 29) times of the land area. The surface area of the earth is about 510 million square kilometers. What is the land area of the earth?

Let X be the land area
X+2（13/29）X=5.1
X=5.1/3（13/29）
X=1.479
The land area is 147.9 million square kilometers

If the symmetry axis of the ellipse is the coordinate axis, the sum of the length of the major axis and the minor axis is 18, and the focal length is 6, then the ellipse equation is? 2,
High school ellipse, solving
1. If the symmetry axis of the ellipse is the coordinate axis, the sum of the length of the major axis and the length of the minor axis is 18, and the focal length is 6, then the ellipse equation is?
2, the eccentricity of ellipse x ^ 2 / 16 + y ^ 2 / 8 = 1 is?

If the symmetry axis of the ellipse is the coordinate axis, the sum of the length of the major axis and the minor axis is 18, and the focal length is 6, then the elliptic equation a > b > 0, 2A + 2B = 18, 2C = 6 = > A + B = 9, C = 3 and a & # 178; = B & # 178; + C & # 178; = B & # 178; + 9 = > (a + b) (a-b) = 9 = > A-B = 1 = > A = 5, B = 4 = > the elliptic equation is: X & # 178 / 25 + Y & # 178 / 16 = 1 or

The following statement is incorrect: A: - 0.5 is a negative number. B: 0 is neither an integer nor a negative number. C: integers and fractions are collectively called rational numbers
0 is the smallest rational number

There is no minimum rational number for D
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Given that y = f (x) is an even function, if x ≥ 0, f (x) = x & # 178; - 4x + 3, then the monotone increasing interval of F (x) is_________

(2) When x ≥ 0, f (x) = x2-4x + 3 The function y = f (x) is a decreasing function on [0,2] and an increasing function on [2, + ∞) When x ＜ 0, - x ＞ 0, ∵ f (x) is even function, ∵ f (x) = f (- x) = x2 + 4x + 3 (10) y = f (x) is an increasing function on [- 2,0] and a decreasing function on (- ∞, - 2]

If the reciprocal of 3 / 3 of a and 2a-9 of 3 are opposite to each other, then a = ()

The reciprocal of three out of a: a out of three
Opposite numbers: (A / 3) = - (2a-9 / 3)
The solution is a = 3

Solve the system of linear equations of three variables 5x + Y-2 = Z, x + 5Y + Z = - 2, x + y + 5Z = 10

(1) + (2) 6x + 6y = 0 = > x + y = 0 substituting (3) = > 5Z = 10 = > z = 2
The solutions of F equations are x = x, y = - x, z = 2 [x takes any value]

Can we use dichotomy to explain this problem in detail: the interval of zero point of function f (x) = 3 ^ x-x ^ 2

f(0)>0
f(-1)

If the parabola y = x2 + BX + C has only one intersection with the X axis and passes through points a (m, n) and B (M + 6, n), then n=______ ．

When x = - B2, y = 0, and b2-4c = 0, that is B2 = 4C. And ∵ points a (m, n), B (M + 6, n), ∵ points a and B are symmetric with respect to the straight line x = - B2, ∵ a (- b2-3, n), B (- B2 + 3, n). Substituting the coordinates of point a into the parabolic analytical formula, n = (- b2-3) 2 + B (- b2-3) + C = − 14b2 + C + 9 ∵ B2 = 4C and ∵ n = − 14 × 4C + C + 9 = 9 ：9．

If a ＜ 0, B ＞ 0, C ＞ 0 is known, then the vertex of the parabola y = ax & # 178; + BX + C is at the third point___ Quadrant

The first quadrant x is greater than 0 C is greater than 0