A few junior high school questions, a few junior high school math questions

An = three-quarters ab, bc = half ab, mn = one-half ab, so the result is three-quarters.

According to the condition you gave, it is am=mn=cn=nb, the line segment ab is divided into four equal parts, an=3 4ab, bc=1 2ab, mn=1 2ab, that is, (3 4-1 2+1 2)=3 4ab

According to the title, m, c, and n are the quartile points of ab, i.e., an=3 4ab, bc=1 2ab, mn=1 2ab, an-bc+mn=3 4ab-1 2ab+1 2ab=3 4ab

According to the known conditions: an=3 4ab, bc=1 2ab, mn=1 2ab

So, an-bc+mn=3 4ab-1 2ab+1 2ab=3 4ab

The points on the line segment are a m c n b and their distance is equal Let ab be 4 then am=mc=cn=nb=1 where an-bc+mn=3-2+2=3 3 is 3 4 of 4

Draw the graph and know that m and n are the quartile points of ab, an=3 4ab, bc=1 2ab, mn=1 2ab, an-bc+mn=3 4ab-1 2ab+1 2ab=3 4ab

I'm an elementary school student, so I'm sure I won't!!

A root is 2 substituted into the original formula to obtain m=-1, and then m=-1 is substituted into the original formula to solve the binary equation).

2.(5x-1) (x-1) (multiplication of crosses) This is very simple, using the properties of the set to extrapolate a-1=4 a=5 or a-1=5 a=4, because the second is unsolvable, so the answer is a=5

2 (several generations greater than 1).

The position of x is replaced by 2x+1) i.e. 2(2x+1)+1

Through a root of 2, we can know m=-1, and then substitute the original formula to solve the binary equation) 2(5x-1) (x-1) (cross multiplication).

1) There is a point p on the be and ec so that the quadrilateral pade or pdae is a right-angled trapezoid, and x=3, or 8

2) There is a point p on the be and ec so that the quadrilateral pade or pdae is a parallelogram, and x=1 or 11 is obtained

3) Under the premise of 2), as long as the adjacent edges are equal, the diamond shape can be obtained, so do the math.

When x=1, the length of de is over d and df is perpendicular to f, then df=fc=4 and ec=6, so ef=2, in the rt triangle def, find de=root number 20, which is not equal to 5

So it can't be diamond-shaped.

When x=11, the similarity is obtained, and finally a diamond can be formed.

1) When x is 3 or 8.

2) When x is 1 or 11.

3) No, I can't. Because ad=5, and de=2 3....There is a diamond theorem: a quadrilateral with all four sides equal is a diamond. It can be seen that it cannot be established.

It's fine if it's the first year of junior high school, because I'm in the first year of junior high school right now.

or or 11

3.From 2, it is not true when bp=1.

When bp=11, the quadrilateral vertices with the points p,a,d,e are parallelograms, so ep=ad=5

If D is df perpendicular to f, then df=fc=4, so fp=3 so dp= fp 2+df 2= 3 2+4 2=5 so ep=dp, so the parallelogram pdae is rhomboid.

Therefore, at this time, the quadrilateral with p, a, d, e as vertices can form a diamond.

1)3 Because the DF construct an isosceles right-angled triangle DF through the D point to the BC perpendicular line DFC should be a right-angled trapezoidal shape with the points P, A, D, E as the vertices.

So ap df so ap=df =fc=cd*sinc=4 has because e is the midpoint of bc ec=6 so ef=2 and because ad=pf =5 pe=3

And because be=6, x=bp=3

3) No, because PE=5 EF=2 PF=4 5 2 4 cannot form a right triangle.

No. 1 is a triangle with three toothpicks, side length = 1, number of toothpicks a1 = 3 No. 2 is four triangles with nine toothpicks, side length = 2, number of toothpicks a2 = 3 + 2 * 3 = 9

The nth figure is side length = n, and there are 3n more toothpicks on the side of the 1 side length = n-1 of the (n-1) figure, then an=a(n-1)+3n, there is:

an-a(n-1)=3n

a(n-1)-a(n-2)=3(n-1)

a3-a2=3*3

a2-a1=3*2

All equations are added to give :

an-a1=3(2+3+..n) an=a1+3(2+3+..n)=3(1+2+..n)=3n(n+1)/2

The nth figure has 3n(n+1) 2 toothpicks.

1. Let A complete x per hour, B completes y per hour, and the time required to complete 80% of the work is x

Get: t=3 (hours).

2. Set the original plan to complete the task in x days, and the original work efficiency is y: 300yx=250*2y*(x-20): x=50 (days).

3. It took x days to complete the cooperation with the design.

Then: 1 6 + (1 4 + 1 6) x = 1

Get: x=2 (days).

A's remuneration is: 1 4 * 2 * 600 = 300 (yuan) B's remuneration is: 1 6 * 2 + 1) * 600 = 300 (yuan) This is my answer, it may be in a different format than what you requested, but it can provide you with a reference.

Study hard!

1、（1/3+1/5）x=;x = hours.

x*50%=250*(x-20);x = 50 days 3, set 2 people to cooperate x days later, 1 4 + 1 6) * x = 1-1 6

x=2, then A completes 2*1 4=1 2, and B completes 1-1 2=1 2

That is, two people have the same amount of work!

Therefore, A and B each get 600 * 1 2 = 300