Kneel for detailed process 20, kneel for detailed process

What kind of question?,I'm going to go to the second year of junior high school and below.。

This question should be discussed on a case-by-case basis:

There are two key points: x=2 and x=-10;

1) When x 2, x+10|=x+10

x-2|=x-2

The original inequality is:

x+10-(x-2)≥8

x+10-x+2≥8

Taking into account the prerequisites, it is obtained: x 2

2) When -10 x<2, x+10|=x+10

x-2|=-(x-2)

The original inequality is:

x+10-[-x-2)]≥8

x+10+(x-2)≥8

2x+8≥8

x 0 takes into account the prerequisites: 0 x<2

3) When x<-10, x+10|=-(x+10)

x-2|=-(x-2)

The original inequality is:

x+10)-[x-2)]≥8

x-10+x-2≥8

In this case, it is not established and there is no solution;

To sum up, the solution of the original inequality is: x 0

1) Because a parabola and the parabola y=-1 4x2-3 have the same shape and opening direction.

The quadratic coefficient of the parabola is 1 4

And because the vertex coordinates are (-2,4).

So the analytic formula for the parabola is as:

y=（－1/4)*(x＋2)^2＋4

i.e.: y x 2 4 x 3

2) Move 7 units upwards and 2 units to the left.

Spread method escort refers to.

Let a(x1,y1) b(x2,y2) respectively bring in the elliptic equation, subtract the two equations, and use the midpoint coordinates to obtain the slope bucket of the straight reed wiring.

It is known from i = u r, p = ui: r = u p so r = 110 1500 = 121 15 is known from u = u1 + u2 in a series circuit.

The voltage applied to the resistor should be 220-110=110V, so the resistance of the resistor is 121-15 ohms.

2) += 1500 watts (750 watts for electrical appliances and resistors) 3) In order to make the electrical appliances work normally, it is too wasteful of silver and dry electricity.

Two appliances labeled 110V 1500W can be used. Carried out in series in series in a 220V power supply.