A few math problems in the second year of junior high school are to be solved by masters!! Urgent!!!

Fill a vacancy. 1 （x+6）（x-1）=x2+5x-6,b=-6 （x-2）（x+1）=x2-x-2, a=-1

x2+ax+b=x2-x-6=(x-3)(x+2)

2 x3+3x=x(x2+3), the length of the other side = x2+3, the circumference = 2 (x2+x+3).

3 Cross-section = -6 k, longitudinal intercept = 6, area = |-36/k|2 = 24, k = 3 4 or -3 4

Decompose the factor. 1 25（m+n）2-（m-n）2=4（3m+2n）（2m+3n）

x-y）2-169（x+y）2=(11x-11y+13x+13y)(11x-11y-13x-13y)=- 4(12x+y)(x+12y)

3、a（n-1）2-2a（n-1）+a=a[n-1）2-2（n-1）+1]=a（n-1-1）2=a(n-2 )2

1. According to the topic, b=6 (-1)=-6, a=-2+1=-1, original formula=x -x-6=(x-3)(x+2).

2. One side is x, the other side is (x +3x) x=x +3, perimeter = 2 (x +x+3) = 2x +2x + 6

3. According to the title, 1 2 6 |-6/k|=24, solution |-6/k|=8，k=±3/4

1. Original formula = (5m+5n+m-n)(5m+5n-m+n)=(6m+4n)(4m+6n)=4(3m+2n)(2m+3n).

2. Original formula = (11x-11y+13x+13y)(11x-11y-13x-13y)=(24x+2y)(-2x-24y)=-4(12x+y)(x+12y).

3. Original formula = a[(n-1) -2(n-1)+1]=a(n-2).

(a^2-5)^2=b^4

a 2-5 = b 2 or a 2-5 = -b 2

A2-b 2 = 5 or A2 + b 2 = 5

An equation has four unknowns, and if there are no other conditions, it can only be solved here.

m^2=a-n...1)

n^2=a+m...2)

1)-(2) De:

m^2-n^2=-(m+n)

m+n)(m-n)=-(m+n)

m+n≠0 are divided by (m+n) on both sides to obtain:

m-n=-1

1)-(2) De:

m^2+n^2=2a+m-n=2a-1

Both sides are subtracted by 2mn

m^2+n^2-2mn=2a-2mn-1

m-n)^2=2a-2mn-1

1)^2=2a-2mn-1

2a-2mn=2

a-mn=1

Solution: Subtract the two equations to obtain: n 2-m 2=m+n (n+m)(n-m)=m+n

Because m+n≠0, so:n-m=1.

a-mn=m^2+n-mn=m(m-n)+n=m(m-1-m)+m+1=1。

Subtract from m2=a-n, n2=a+m, and m2-n2=(a-n)-(a+m).

Then there is (m+n)(m-n)=-(m+n) so m-n=-1 from m2=a-n to get a=m2+n

So a-mn=m2+n-mn=m(m-n)+n=-m+n=1

Solution: Set up each narrow road to disperse x people.

Then 3 of a kind passes 3x people.

There are 1800-3x for people passing through wide roads.

The column formula is 3x 140 3 + (1800-3x) 200 mu stuffy 3 solution x fast digging bend 8400 11

So x 764

A: The number of students who need to pass through each narrow staircase should be within the range of 764 students.

The floor cavity let the master I used to use the mobile phone on the now to make up for the Wu Han bureau set up a narrow staircase every minute out of the old head x people.

There is 3 (3x+200) = 1800

The number under the root number is non-negative, so a is greater than or equal to 0

The root number a is greater than or equal to 0, and because a + the root number a = 0, a is less than or equal to 0 so that both conditions are true, so a = 0

Then under the root number (square of a) = 0

ABM is always an isosceles right triangle, map= mpa, ma=mp, pass m as md x-axis in d, as pe md in e, then mep is always isosceles right triangle, and then mc ab in c, easy to verify mca mep(asa), mc=me, and ed=pn=on, mc= ab me=mc= ab, md=me+ed=on+ ab, md is a fixed value of 2, the value of on+ ab is unchanged, and its value is 2

The value of on+(1 2)ab is a fixed value, which is always equal to 2

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