Divide both sides of 5x equal to 8x by X to get 5 equal to 8. The four mistakes are summarized as follows: the equation itself is wrong. Xiao Hong: the equation has no solution

Divide both sides of 5x equal to 8x by X to get 5 equal to 8. The four mistakes are summarized as follows: the equation itself is wrong. Xiao Hong: the equation has no solution

You can't divide both sides by X, because x can be 0

Equation 1 + 80% x = 72x one ninth

1 + 80% x = 72x 1 / 9
1+0.8x=8
0.8x=7
8x=70
x=70/8
x=35/4

Equation: 80 / 9 (x + 9) = 4

9(x+9)=80/4
9x+81=20
9x=-61
x=-61/9

Second order mixed partial derivatives of Z = sinxcosy

See the figure below:

A highway has been built. After 2 / 5 km, there are still 2 / 5 left. This highway is () A. the length of the road that has been built B. the length of the road that has not been built C. the length of the road that has been built is the same as that of the road that has not been built

Choose a
∵ repaired length = 2 / 5 km,
Total length = 2 / 5 (1-2 / 5) = 2 / 3 (m)
That is to say, the length without repair = 2 / 3 × 2 / 5 = 4 / 15 (m)
2 / 5 > 4 / 15
The repaired length
Hope to help the landlord!

The symmetry axis of the image of quadratic function y = (x-1) 2-2 is a straight line______ ．

∵ y = (x-1) 2-2 is the vertex form of parabola. According to the coordinate characteristics of vertex form, the axis of symmetry is a straight line x = 1

The domain of definition of the function f (x) = 4 of degree X-2 of degree x + 1 + 3 is [negative half, half]
1. Let t = 2 x times, find the value range of T
2. Find the range of function f (x)

1. F (x) = 4 ^ X-2 ^ (x + 1) + 3 = (2 ^ x) ^ 2-2 * 2 ^ x + 3, let t = 2 ^ x, because x ∈ [- 1 / 2,1 / 2], the value range of T is: [2 ^ (- 1 / 2), 2 ^ (1 / 2)], that is [√ 2 / 2, √ 2] 2, replace 2 ^ x with T, then f (x) = (2 ^ x) ^ 2 * 2 ^ x + 3 = T ^ 2-2t + 3 = (t-1) ^ 2 + 2 = g (T) the minimum value of function g (T) is g (1) = 2 ∵ t

Given that real numbers a and B satisfy the following conditions: a · B = 1, then the value of 1A2 + 1 + 1b2 + 1 is______ ．

∵ 1A2 + 1 + 1b2 + 1 = A2 + B2 + 2a2b2 + B2 + A2 + 1, ∵ when a · B = 1, a2b2 = (AB) 2 = 1 ∵ the original formula = A2 + B2 + 21 + B2 + A2 + 1 = 1

How to draw the common tangent of two circles in CAD isometric drawing

L + space, enter the straight line command, press and hold shift, right-click to select "tangent point", click one of the circles, then right-click to select "tangent point", and then click another circle, and the common tangent line will come out. This method is taught by the teacher, but not in the book

3:40 equals () 5 and a quarter of a ton equals () ton () kilogram

3. 40:00 5 tons 41 kg