Question

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Answer 1

1. 1) (x-2)²=x²-4x+4

2) (3m+9n)²=9m²+54mn+81n²

3) (c+8)(c-8)=c²-64

4) (2a+5b)(5b-2a)=25b²-4a²

2. 1) 100-a²=(10-a)(10+a)

2) x²+10x+25=(x+5)²

3) 36y²-49=(6y-7)(6y+7)

4) 16a²-24ab+9b²=(4a-3b)²

3.(m-1)(m+1)-(m-3)²=m²-1-(m²-6m+9)=m²-1-m²+6m-9=

=6m-10=2(3m-5)

4. (2x+5)(x-6)+2(3x+2)(3x-2)=5(2x+1)²+11

2x²-12x+5x-30+2(9x²-4)=5(4x²+4x+1)+11

2x²-7x-30+18x²-8=20x²+20x+5+11

20x²-7x-38=20x²+20x+16

20x²-20x²-7x+20x=16+38

13x=54

х=4 2/13

Ответ: 4 2/13

5. (2b-1)²-(b+2)²=(2b-1+b+2)(2b-1-b-2)=(3b+1)(b-3).