Задание 166

Решение:

• \({\largeа)}\ 5-(5-(5-(5-x)))=x;\)
• \(\phantom{\largeа)}\ 5-(5-(5-(5-x)))=5-(5-(5-5+x))=5-(5-x)=5-5+x=x\)
• \({\largeб)}\ x-(x-(x-(x-5)))=5;\)
• \(\phantom{\largeб)}\ x-(x-(x-(x-5)))=x-(x-(x-x+5))=x-(x-5)=x-x+5=5\)
• \({\largeв)}\ a(b-c)-b(a+c)+c(b+a)=0;\)
• \(\phantom{\largeв)}\ a(b-c)-b(a+c)+c(b+a)=ab-ac-ab-bc+bc+ac=0\)
• \({\largeг)}\ a(b+c)-b(a+c)-c(a-b)=0;\)
• \(\phantom{\largeг)}\ a(b+c)-b(a+c)-c(a-b)=ab+ac-ab-bc-ac+bc=0\)
• \({\largeд)}\ (x-1)(x+1)=x^2-1;\)
• \(\phantom{\largeд)}\ (x-1)(x+1)=x^2-x+x-1=x^2-1\)
• \({\largeе)}\ (x-2)(x+2)=x^2-4.\)
• \(\phantom{\largeе)}\ (x-2)(x+2)=x^2-2x+2x-4=x^2-4\)