1. (x-5)(x+5)=

x²-5²

x²-25

2. (4x+7y)(4x-7y)=

(4x)²-(7y) ²

16x²-49y²

3. (10+ab)(ab-10)=

(ab+10)(ab-10)

a²b²-100

4. (3a+2)(2-3a)=

(2+3a)(2-3a)

4-9a²

5. (a⁵-b³)(a⁵+b³)=

(a⁵)²-(b³)²

a¹⁰- b⁶

6. (a\2-b\5)(a\2+b\5)=

(a/2)²-(b/2)²

a²/4 - b²/25

2.

1. (6x-y)(6x+y)+(x+3y)(3y-x);

36x²-y² + (3y+x)(3y-x)

36x²-y² + 9y²-x²

35x² - 9y² + 9y²

35x² + 8y²

2. (x+7)²-(x-11)(x+11);

x²+14x+49-(x²-121)

x²+14x+49-x²+121

14x+49+121

14x+170

№3

1. (9x-1)(9x+1)-3x(27x-5)=44

81x²-1-81x²+15x=44

-1+15x=44

15x=44+1

15x=45

x=45/15

x=3