Объяснение:
Формула: (a±b)²=a²±2ab+b²
1) (x-4)²-16= x²-2x·4+4²-16=x²-8x+16-16=x²-8x
2) 10a+(a-5)²= 10a+(a²-2·a·5+5²)= 10a+(a²-10a+25)=10a+a²-10a+25=a²+25
3) (3m-7n)²-(3m+7n)²=(3m)²-2·3m·7n+(7n)²-((3m)²+2·3m·7n+(7n)²)=
=9m²-42mn+49n²-(9m²+42mn+49n²)=9m²-42mn+49n²-9m²-42mn-49n²=-84mn
4) (6a-3b)²+(9a+2b)²= (6a)²-2·6a·3b+(3b)²+(9a)²+2·9a·2b+(2b)²=
=36a²-36ab+9b²+81a²+36ab+4b²=117a²+13b²
5) b(b-3)-(b-4)²=b²-3b-(b²-8b+16)=b²-3b-b²+8b-16=5b-16
Объяснение:
Формула: (a±b)²=a²±2ab+b²
1) (x-4)²-16= x²-2x·4+4²-16=x²-8x+16-16=x²-8x
2) 10a+(a-5)²= 10a+(a²-2·a·5+5²)= 10a+(a²-10a+25)=10a+a²-10a+25=a²+25
3) (3m-7n)²-(3m+7n)²=(3m)²-2·3m·7n+(7n)²-((3m)²+2·3m·7n+(7n)²)=
=9m²-42mn+49n²-(9m²+42mn+49n²)=9m²-42mn+49n²-9m²-42mn-49n²=-84mn
4) (6a-3b)²+(9a+2b)²= (6a)²-2·6a·3b+(3b)²+(9a)²+2·9a·2b+(2b)²=
=36a²-36ab+9b²+81a²+36ab+4b²=117a²+13b²
5) b(b-3)-(b-4)²=b²-3b-(b²-8b+16)=b²-3b-b²+8b-16=5b-16