3 Math help, yes! 2 Math help, there must be a process, thank you, I will definitely adopt!

Hello landlord: I will introduce you to a variety of methods.

One. Square:

Use large squares to subtract two small rectangles.

Large square area = (squared.

Small rectangle = height * width = square Shadow = square of 33a - square of 7a = square of 26a.

Two. s yin = 6a (

One. Circle: In the same way, the great circle minus the area of two small circles.

Great circle = 2 * (a+b) squared Two small circles are 2 a squared and 2 b squared.

Subtract to =4ab

Two. S Yin = (2A+2B)) A - B = (A +B +2ab-A -B) = 2ab

I wish the landlord learning and progressing.

Square: Use a large square to subtract two small rectangles.

Large square area = (squared.

Small rectangle = height * width = square Shadow = square of 33a - square of 7a = square of 26a.

Circle: In the same way, the great circle minus the area of two small circles.

Great circle = 2 * (a+b) squared Two small circles are 2 a squared and 2 b squared.

Subtract to =4ab

Hope, thank you! ~

Left: 6a (squared.)

Right: [a+b)squared-asquared-bsquared]=2 ab

6a×（2a+

6a 33a square - 14a square.

19a squared.

2.2 (a+b) squared 2 a square 2 b squared.

2 (a-squared, 2ab+b-squared, a-squared-b-squared)2-2ab

4πab

The result is: (a-9)*(a+9) (6-x)*(6+x) (1-4b)*(1+4b) (m+3n)*(m-3n).

13x+2y)*(13x-2y) (3ap+bq)*(3ap-bq) (7/2a+xy)(7/2a-xy)

The formula (a 2-b 2) = (a + b) * (a - b) is used as a whole

If it's so simple, it's better to go through the textbooks.

Original 3 (x +10x+25)-2 (9-6x+x )+81-x )=42x+138=42 ( 4 3)+138=82

I wish you a happy life and progress in your studies.

493 9 Simplify to the end to get these things, but I don't think it's easy enough.

2)=2 2+4 refers to the Zen god group 2 2=6 2 2=6

5) Blind dust = 80 5- 50 2 = 400- 100 = 20-10 = 10

Hope, thank you!

The arithmetic square root of 81 is 9, and the square root is 9 and -9

Others are similar.

（1）y=2x-4000

When x=500, y=-3000

When x=1000, y=-2000

When x=1500, y=-1000

When x=2000, y=0

When x=2500, y=1000

When x=3000, y=2000

When x=3500, y=3000

When x=4000, y=4000

2) When x>=2000, y>=0

Buses don't lose money.

（1）y=2x-4000

x=500, y=-3000

x=1000, y=-2000

x=1500, y=-1000

x=2000, y=0

x=2500, y=1000

x=3000, y=2000

x=3500, y=3000

x=4000, y=4000

2) When x>=2000, y>=0

Buses don't lose money.

x=500y=-3000 x=1000y=-2000 x=1500y=-1000 x=2000y=0 x=2500y=1000

x=3000y=2000 x=3500y=3000 x=4000y=4000

x=2000 So reach more than 2000 people per month, so you won't lose money.

1/2mn + 19/8 squared. Hope.

18.(1) Congruent triangles are BCD and ace.

Rationale: BCD= AC, BC=AC, DC=EC2) Rotate BCD 60° to the right to obtain and ace19 ②abc≌△def

ll is the first day of junior high school Please click on the lower right corner to select the satisfactory answer.

18.(1) Congruent triangles are BCD and ace. Reason: BCD= AC, BC=AC, DC=EC.

2) The cavity and the disturbance resistant BCD are rotated 60° clockwise to obtain ACE19②③abc≌△defaas

Xie Yu cavity: 18△bcd≌△ace

Rotate the needle 60° with SAS)BCD to obtain a leaky ace