Question

Докажите тождества:
-(-7х)-(6+5х)=2(х-3)
36-(-(9с-15))=3(3с+7)

Answer 1

1) -(-7x)-(6+5x)=2(x-3)
7x-6-5x=2x-6
2x-6=2x-6 доказано
2) 36-(-(9с-15))=3(3с+7)
36-(-9с+15)=9с+21
36+9с-15=9с+21
9с+21=9с+21 доказано