Solving! Hurry, hurry! Junior High School Math! Hurry up and add a bounty!

Big brother, you don't have this picture, how do you see it, please take a photo.

I don't figure out what you want me to do.

Let the same percentage of growth be x

then there is the first year: 200

Second year: 200 (1 x).

Year 3: 200 (1+x) 2

A total of 1,400 trees were planted in three years, so there is.

200 200(1 x) 200(1+x) 2=1400 Simplification: x 2 3x-4 0

x＋4）（x－1）＝0

Because x>0, x1 100

Set to x200+200(1+x)+200(1+x)(1+x)=1400 simplification. x2+3x-4=0

x-1)*(x+4)=0

The solution is x=1, so this percentage is 100%.

I'll give you the answer at half past ten, I'm in trouble right now.

2.Put the cuboid, the shortest straight line between two points, take the paper and fold one, you immediately know, ha.

For the first question, you use geometric congruence proof: But if you use your formula, x=8 is a wrong solution! The Pythagorean theorem gets 25!

It's not x +(8 x-3).

Primitive Filial Piety = x-3 + (8 x-3) + 3 T = x-3, Primitive = T + 8 T + 3 2 times the root number (t times 8 t) Clear then + 3 = 4 times the root number 2 + 3

The minimum value is 4 times the root of the shed number 2 + 3

The original formula is x+8 (x-3) No, if it's not So's, you don't need to look at the following.

Let t=x-3, t>0 original = 3 + t + 8 tt + 8 t> = 2 * root number (t*8 t) = 4 root number under 2 original minimum value 3 + 4 root crack cherry number under 2

Solution: (1) p(x,0), let c(x,y). Using the two-point formula, the equation for the straight line AB is y=(-3 4)(x-4)=3(1-x 4), that is, the length of pc=y=3(1-x4), where x(0,4).

2) CD AB, according to the relationship between CD and AB slope, there is KCD=4 3. Let d(0,y0) then [y0-3(1-x 4)](0-x)=4 3. ∴y0=3(1-x/4)-4x/3。

The formula for the area of a triangle represented by vertex coordinates has the absolute value of s pcd=(1 2)丨x,y,1 x,0,1 0,y0,1丨. ∴s△pcd=(1/2)x(3-3x/4)。and s pcd = (2 3) (3 x 4) (3-3x 4) (2 3) [(3-3x 4+3x 4) 2] 2=3 2.

That is, when 3-3x 4=3x 4 and x=2, the maximum value is 3 2. (3) Analyze the slope of straight line PC, CD and PD, and make PCD RT, only when D and O coincide. ∴(3-3x/4)/x=4/3，x=36/25。

4) Overlap along PD, point C can only fall on the Y axis, let the drop point of point C be E, then PE=pc=Y, by the Pythagorean theorem, OE 2=PE 2-OP 2=(3-3X 4) 2-X 2=(3-7X 4)(3+X 4)>0, consider X (0,4), 0