573 ^ 2 * 31-427 ^ 2 * 31 simple calculation by factorization

573 ^ 2 * 31-427 ^ 2 * 31 simple calculation by factorization

573^2*31-427^2*31
=31x(573^2-427^2)
=31x(573+427)(573-427)
=31x1000x146
=31x146000
=(30+1)x146000
=30x146000+146000
=4380000+146000
=4526000

As shown in the figure, in △ ABC, the bisector of ∠ ABC and the bisector of the outer angle of ∠ ACD intersect at point O. if ∠ a = 40 °, calculate the degree of ∠ BOC
If the picture can't be sent out, can it be done,

Because there is no picture, please draw your own picture according to the letters. The formula (1) is changed to & frac12; the formula (1) is changed to & frac12; the formula (1) is changed to & frac12; the formula (1) is changed to & ACD = & frac12; the formula (1) is changed to & ABC + & BOC

A simple algorithm of 28 times 29 times 30 minus 28 times 29 times 5 minus 25 times 28 times 29
And 11111 by 99999

28 times 29 times 30 minus 28 times 29 times 5 minus 25 times 28 times 29 = 28 × 29 × (30-5-25) = 28 × 29 × 0 = 0 11111 times 99999 = 11111 × 11111 × 9 = 123454321 × 9 = 1111088889

Change the following determinant into triangle determinant, the first line is 2, - 5,3,11,3, - 1,3
Change determinant into upper triangle determinant and calculate its value
First line 2 - 5 3 1
Second line 1 3 - 1 3
The third line 0 1 - 5
Line 4 - 1 - 4 2 - 3

2 -5 3 1
1 3 -1 3
0 1 1 -5
-1 - 4 2 - 3 line 1 minus line 2 × 2, line 4 plus line 2
=
0 -11 5 -5
1 3 -1 3
0 1 1 -5
0 - 1 10 expand by column 1
=
-11 5 -5
1 1 -5
-1 10 * (- 1) ^ (1 + 2) column 1 plus column 2
=
-6 5 -5
2 1 -5
0 1 0 * (- 1) expand by line 3
=
-6 -5
2 -5 *(-1)*(-1)^(2+3)
=30+10
=40

What is 6000 divided by + 6.84

6000/6.84=600000/684=877.19

It is proved that the equation x = a * SiNx + B, where a > 0, b > 0, has at least one positive root x0, and x0

Let f (x) = x-asinx-b
f(0)=-b

Simple calculation of 3.6 * 8.4 + 7.2 * 0.8

3.6*8.4+3.6*2*0.8=3.6*8.4+3.6*1.6=3.6*(8.4+1.6)

3x + 4Y = 104y + 2Z = 305x-2z = 20, find the values of X, y and Z

3X+4Y=10 (1)
4Y+2Z=30 (2)
5X-2Z=20 (3)
(1) - (2) get
3x-2z=-20 （4）
(3) - (4) get
2x=40
Substituting x = 20 into 4 gives z = 40
Substituting (1) gives y = - 25 / 2
To sum up
x=20 y=-25/2 z=40

4200 divided by 35

4200/35 =60*70/35=60*(70/35)=60*2=120

It is known that the inclination angle of the straight line L is twice that of the straight line y = x + 1, and if it passes through the fixed point P (3,3), then the equation of the straight line L is

Because the slope of the line y = x + 1 is 1, the inclination angle is 45 degrees, so the inclination angle of the line L is 90 degrees
Because it passes through the fixed point P (3,3), the linear equation is x = 3