A few junior high school math and one junior high school math

1.Solution: Let the speed of ship A x1, the speed of ship B x2, and the speed of water a. Downstream speed = ship speed + water speed, reverse water speed = boat speed - water speed, and the time to go down the water to a certain time at a uniform speed is t.

The range from A to B t*(x1+a), and the range t*(x2+a) from A to C is > t*(x2+a) to x1>x2t1= (x1-a), t2= (x1-a)-[t*(x2+a)] (x2-a).

Score = (x1-a)(x2-a)-[t*(x2+a)(x1-a)] (x2-a)(x1-a).

Remove the brackets and merge the same kind of terms, =2at(x2-x1) (x1-a)(x2-a)x1-a>0, x2-a>0 x1>x2 is x2-x1<0 so t1-t2<0 i.e. t1 what does it mean?

(1) From the rectangular ABCD, it can be seen that the angle DAC = angle BCA can be known by the folding, the angle DAG = angle GAC = angle DAC 2, the angle BCE = angle ACE = angle BCA 2

So, angular gac = angular ace

So, AG is parallel to CE

And because CG is parallel to AE

So, the quadrilateral AECG is a parallelogram;

2) When the quadrilateral AECG is a diamond, ae=ce, so, the angle ace=angle eac, thus, the angle eac=angle dag=angle gac=30 degrees.

AB=3cm, then BC=root number 3cm, that is, BC=root number 3cm, quadrilateral AECG is diamond-shaped.

Solution: (1) From the meaning of the title, gah= 12 dac, ecf= 12 bca, quadrilateral abcd is a rectangle, ad bc, dac= bca, gah= ecf, ag ce, and ae cg

The quadrilateral AECG is a parallelogram;

2) The quadrilateral AECG is a diamond, F, H coincide, AC=2BC, in RT ABC, let BC=X, then AC=2X, in RT ABC AC2=AB2+BC2, that is, (2X)2=32+X2, the solution is X= root number 3 (X=- root number 3 rounded), that is, the length of the line segment BC is the root number 3cm

1.Original = [23 3-(-1) 7+(-23) 3] [7 4 7 2 (-21 2)-5 3].

-130)1 4 is -130 and 1/4 of the way, where the sum of the 3rd power of 23 in the first parenthesis and the 3rd power of (-23) is equal to 0, and the rest can be calculated according to the four operations.

2.How is it the same as the first question? 3.=

10x+4.(x+1)/(x-3)=[(x-1)/4]+2∴(x+1)/(x-3)=(x+7)/4

4(x+1)=(x-3)(x+7)

4x+4=(x^2)+7x-3x-21

4=(x^2)-21

x 2 = 25 i.e. x squared = 25

x=5 or x=-5

Simplify. Sorted out to 2x=

x= i.e. 3/4

3x) 2]+5x-[(x 2) 2]-(9x 2)+, where x=1 10

9x^2)+5x-(x^2)/2-(9x/2)+1/2-x/2=[(17/2)x^2]+1/2

Substituting x=1 10 into the above result, we obtain.

117 200 is 117 per 200

Can the topic be written better?