The math problems in the third year of junior high school are in a hurry! Please come in and help 10

1。Here, the root number and denominator are removed, and the numerator is multiplied by the denominator.

2。The square difference formula (26+10) (26-10) = 36*16 is used in the root number; Root number: 36*16=6*4=24

3。The move yields x +2x=0, i.e. x(x+2)=0 x=0 or x=-24If the two roots are equal, then δ=(2k) -4*1*4=0 k=2 or -25. Let the length of the three sides be x, x+1, x+2;

Yes: x +(x+1) +x+2) =50 : 3x +6x-45=0 to get x=3 and the maximum side is 5

Mathematics is the science of thinking, and I wish the landlord a better level of learning!

1: The numerator and denominator are multiplied by the denominator at the same time, and then the numerator becomes, b multiplied by the sign 3ab. That's it.

2: Root number 262 102 Root number (26 10) (26 10) Root number 36 16 6 4 24

3: The root is x equal to 0 or the square plus 2x is equal to 0, the recipe knows that x(x+2)=0, and the value of x can be found.

4: The value of k is plus or minus 2. The equation formula can be obtained as the square of (x+k) - the square of k + 4, which can also be written as the square of (x+k) = the square of k -4, and the solution of the equation shows that x=-k+ - the square of k under the root number -4, because the two are equal, then it can be seen that the square of k under the root number -4 should be equal to 0, so k is equal to + -2

5: Let the lengths of the three sides be a, a+1, a+2 respectively, according to the Pythagorean theorem, the sum of squares of the two short sides is equal to the third side, we can know that a=3, a+1=4, a+2=5So the longest side is equal to 5

I don't know if the explanation is clear, I try to be as detailed as possible, I hope it can help you!

1. Multiply by the root number 3AB

3. x = -2x to x +2x=0, x*(x+2)=0, x=0 or x=-2

4. (2k) 4*4=0, k=2 or k=-25, let one side be x, one side is x-1, and the other side is x+1, then x +(x-1) +x+1) = 50, the solution is obtained.

x=4, so the maximum side length is 5.

1.Multiply by the root number 3AB

The square of *4 is 6*4=24 under the root number

or x=-24i.e. (2k) squared -4*4=0 k=2 or k=-25Let the side length be x-1 x x+1, then x square + (x-1) square + (x+1) square = 50

3x square + 2 = 50 x = 4

So the maximum is 5

From the title: x-2=w x=w+2

y= 20 w=1 x=1+2=3

15 w=2 x=2+2=4

12 w=3 x=3+2=5

10 w=4 x=4+2=6

Conjecture: y=k x

Bring in to the number of hungry and late: k=60

For example: 20=k 3 gets: k=60).

Then: y=60 Rotten Qiao Li x

From the meaning of the topic, it is broad: 3<=x<=10 1<=w<=7Profit=y*w=60w (w+2)=60 (1+2 w) When w=7, the maximum profit = 140 3

Extend the cf with ab with k

akf≌△afc

kf=cf ak=ac

bm=cmmf=1/2bk=（ab-ac）

The extension cord extending BE and AC is crossed with G

abe≌△aeg

be=eg、ab=ag

em=1/2cg=1/2（ab-ac）

me=mf

In 2007, the green area is x and the population is y; The per capita green area in 2007 was x y, then the green area in 2009 was , and the per capita green area in 2009 was.

So the average population growth rate for these two years is divided by y.

Assuming that the population growth rate should be controlled within x%, the population in 2007 is A, and the per capita green area in 2007 is B.

b(1+21%)a(1+x%)=ba(1+44%)x=19

Therefore, it should be controlled within 19%.

In 2007, green space was a, population was b, green space per capita was a b, and population growth rate was x

In 2009, green space a (1+44%), per capita green space a (1+44%) b(1+x) 2=a b*(1+21%)

x=1/11=

Dude, stop studying, go home and farm. There is also a rural hukou. Ay.

1) Tease; l or bring c(1,6) to y=m x, and the mountain laugh does m=6, y=6 x. Bring d(3,n) to the equation to get n=2

2）；With the two-point formula c, d gives y-6=-2(x-1).

3）；Proof: Angle ADF = Angle BAO, Angle ECB = Angle OBA

Bring c(1,6) to y=m x to get m=6,y=6 x. Bring d(3,n) to the digging and gripping formula, and get the skin grinding n=2

2）；With the two-point formula c, d gives y-6=-2(x-1).

Judgment 3); Proof: Angle ADF = Angle BAO, Angle ECB = Angle OBA

Because ab ac bc, it is concluded that this triangle is an equilateral triangle, i.e., a= b= c=60°

So cosa cos60°=

sinb sin60° 3 2 (2 points of the root number 3).

All three sides are equal, indicating that it is a regular triangle. The corners are 60 degrees. So cosa (,sinb(32)

Equilateral triangle with three angles of 60 degrees. cosa = 1 2, sinb = half of the root number three.