calculation 1)（2+1)(2^2 +1)(2^4 +1).(2^2n +1) 2)100^2-99^2+98^2-97^2+96^2-95^2+.+2^2-1^2 3)（1-1/2^2)(1-1/3^2)(1-1/4^2).(1-1/9^2)(1-1/10^2) 4) (y-1/2)^2 5)(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2 6) 1.2345^2+0.7655^2+2.469*0.7655 7) (x+2y)(x-y)-(x+y)^2 Simplification before evaluation 1）(x+y)+(2x+y/1*2)+(3x+y/2*3)+.+(9x+y/8*9) x=2 ,y=9

calculation 1)（2+1)(2^2 +1)(2^4 +1).(2^2n +1) 2)100^2-99^2+98^2-97^2+96^2-95^2+.+2^2-1^2 3)（1-1/2^2)(1-1/3^2)(1-1/4^2).(1-1/9^2)(1-1/10^2) 4) (y-1/2)^2 5)(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2 6) 1.2345^2+0.7655^2+2.469*0.7655 7) (x+2y)(x-y)-(x+y)^2 Simplification before evaluation 1）(x+y)+(2x+y/1*2)+(3x+y/2*3)+.+(9x+y/8*9) x=2 ,y=9

(1) The original formula = (2-1) * (2 + 1) * (2 ^ 2 + 1) * (2 ^ 4 + 1) * *(2^n+1) =(2^2-1*(2^2+1)*(2^4+1)*…… *(2^n+1) =（2^4-1)(2^4+1)*…… *(2^n+1) =(2^n+1)(2^n-1) =2^2n-1(2)100^2-99^2+98^2-97^2+96^2-95^2+.+2^2-1^2 =(100+99)(100-99)...
How to solve the problem of factorization class
To master the basic methods of factorization --- extraction of common factor, cross phase multiplication, grouping factorization, formula method, etc
Drawing is like|______ Divide the number until the rest is a prime number.
When factoring, we first mention the common factor, and then observe the formula to see if it can cross multiply, and so on
A factoring problem in grade two of junior high school
3x^n y + 9x^(n-1) y^2 + 0.25 x^(n+1)
It's a little unclear
Let's go over the words
3x to the power of N, y plus 9x to the power of n minus 1, y to the power of 2 plus 0.25x to the power of N + 1
It's much easier to extract x ^ (n-1) first
3x^n y + 9x^(n-1) y^2 + 0.25 x^(n+1)
= x^(n-1) * ( 3xy + 9y^2 + 0.25x^2 )
= x^(n-1) * (0.5x + 3y )^2
How to factorize a ^ 2-4-a + 2
It's actually four questions: (factorization)
1.a^2-4-a+2
2.a^8-b^8
3.x^3+3x^2-2x-6
4.15x^3n+9x^2n-6x^n
1. (a+2)(a-2)-(a-2)=(a-2)(a+2-1)
2.(a^4+b^4)(a^2+b^2)(a+b)(a-b)
3.x^2(x+3)-2(x+3)=(x+3)(x^2-2)
4.3x^n(5x^2n+3x^n-2)=3x^n(5x^n-2)(x^n+1)
1. (a + 2 + radical 2) (a + 2-radical 2)
2.(a^4+b^4)(a^2+b^2)(a+b)(a-b)
3. (x + 3) (x + radical 2) (x-radical 2)
4. Er This has not come out yet Sorry
The square of 4A, the square of B - (the square of a + the square of B)
4a²b²-（a²+b²）²
4a²b²-（a²+b²）²
=(2a²b²+（a²+b²）)*(2a²b²-（a²+b²）)
=(a+b)^2*(-(a-b)^2)
=-(a+b)^2*(a-b)^2
-(a-b）²(a+b）²
-（a+b）^2*(a+b)^2
4a²b²-（a²+b²）²
=(2ab)²-（a²+b²）²
=(2ab+a²+b²)(2ab-a²-b²)
=-(2ab+a²+b²)(-2ab+a²+b²)
=-(a+b)²(a-b)²
(x square + 4x + 8) square + 3x (x square + 4x + 8) + 2x square
Factorization
(x^2+4x+8)^2+3x(x^2+4x+8)+2x^2=(x^2+4x+8+x)(x^2+4x+8+2x)=(x^2+5x+8)(x^2+6x+8)=(x+(5+√17)/2)(x+(5-√17)/2)(x+2)(x+4)
For a certain work, Party A does it alone for 4 days and Party B does it alone for 6 days. If Party A does it for 1 day first, then Party A and Party B cooperate to complete the work. If Party A has done it for X days in total, the number of days Party B works for () days, from which the equation ()
A person deposits 20000 yuan into two banks. The annual interest rate of Bank A's deposit is 1.4%, and that of bank B's deposit is 1.44%. After one year, the company will get 286 yuan of pre tax interest. How much is each of the two deposits? Set up an unknown equation and list it
If a works for 4 days, B works for 6 days, if a works for 1 day, then a and B cooperate to complete the work, if a works for X days, then B works for (x-1) days, then the equation can be listed as follows: X / 4 + (x-1) (1 / 6) = 1, someone deposits 20000 yuan in two banks, the annual interest rate of a bank's deposit is 1
(x-1) days, X / 4 + (x-1) / 6 = 1, Party A works for X days, Party B works for (x-1) days, just finished. This column is convenient for calculation
First question:
A does one day more than B, so B works (x-1) days
It can be seen from the question that the work efficiency of a is 1 / 4, and that of B is 1 / 6. The total work quantity is 1,
Then: 1 / 4x + 1 / 6 (x-1) = 1
Second question:
If the deposit in bank a is RMB x, the deposit in bank B is RMB 20000-x
According to: interest = principal × interest rate × number of periods, total interest = interest of Party A + interest of Party B
Expansion = 20000 + 1.44% x = 1.6%
First question:
A does one day more than B, so B works (x-1) days
It can be seen from the question that the work efficiency of a is 1 / 4, and that of B is 1 / 6. The total work quantity is 1,
Then: 1 / 4x + 1 / 6 (x-1) = 1
Second question:
If the deposit in bank a is RMB x, the deposit in bank B is RMB 20000-x
According to: interest = principal × interest rate × number of periods, total interest = interest of Party A + interest of Party B
286 = 1.4% x + 1.44% (20000-x) Stow
If a works for 4 days and B works for 6 days, if a works for 1 day, then a and B work together to complete the work, if a works for X days, then B works for (x-1) days, from which the equation (1 / 4x + 1 / 6 × (x-1) = 1) can be listed
A person deposits 20000 yuan into two banks. The annual interest rate of bank a is 1.4%, and that of bank B is 1.44%. The company will get 286 yuan of pre tax interest after one year. How much for each of the two deposits? Set out to expand
If a works for 4 days and B works for 6 days, if a works for 1 day, then a and B work together to complete the work, if a works for X days, then B works for (x-1) days, from which the equation (1 / 4x + 1 / 6 × (x-1) = 1) can be listed
A person deposits 20000 yuan into two banks. The annual interest rate of bank a is 1.4%, and that of bank B is 1.44%. The company will get 286 yuan of pre tax interest after one year. How much for each of the two deposits? Set the unknown and list the equations
Deposit X Yuan in bank B,
1.4%（20000-x）+1.44%x=286，
The solution is x = 15000
A bank deposit 20000-15000 = 5000
The working days of Party B are (x-1) days, from which the equation (1 / 4x + 1 / 6 (x-1) = 1) can be listed
The deposit of type A is x yuan, and that of type B is (20000-x) yuan
x*1.4%+（20000-x）*1.44%=286
Examples of group decomposition method in factorization of mathematics in grade two of junior high school
(a+b)^2=a^2+2ab+b^2
(a-b)^2=a^2-2ab+b^2
a^2-b^2=(a+b)(a-b)
1.(a+b)^2=a^2+2ab+b^2
(a-b)^2=a^2-2ab+b^2
a^2-b^2=(a+b)(a-b)
How to calculate 3 / 5 (3x + 66) = 4x
Multiply both sides of the equation by 5 to get 3 (3x + 66) = 20x
9X+198=20X
11X=198
X=18
(7X-3)\7=(1+15X)\5
I just figured it out. You're too slow.
But the one who has finished the test first will be chosen
Take 35 on both sides
5(7x-3)=7(1+15x)
35x-15=7+105x
105x-35x=-15-7
70x=-22
x=-11/35
I'm sorry. I'm in the fourth grade
(7X-3)\7=(1+15X)\5
5(7x-3)=7(1+15x)
35x-15=7+105x
105x-35x=-15-7
70x=-22
X = - 11 / 35 question: add a test, thank you