1. 1) (x+7)(x+2)=x²+2x+7x+14=x²+9x+14
2)(y+5)(y²-3y+8)=y³-3y²+8y+5y²-15y+40=y³+5y²-7y+40
3)(a+4)²=a²+8a+16
4)(3y-c)²=9y²-6c+c²
5)(2a-5)(2a+5)=4a²-25
6)(x²+y)(x²-y)=x^4-y²
2. (a-2b)²+4b(a-b)=a²-4ab+4b²+4ab-4b²=a², при а=0,12 и b=2
a²=0.12²=0.0144
3. a)3(1+2x)(1-2x)=3(1-4x²)=3-12x²
b)(a+b)²-(a-b)=a²+2ab+b²-a²+2ab-b²=4ab
4. (4x-3)(4x+3)-(4x-1)²=3x
16x²-9-16x²+8x-1=3x
5x=10
x=2