sedinalana

Verified answer

1)28c/([(c-7)(c+7)]+(c-7)/(c+7)=(28c+c²-14c+49)/[(c-7)(c+7)]=
=(c²+14c+49)/[(c-7)(c+7)]=(c+7)²/[(c-7)(c+7)]=(c+7)/(c-7)
2)(c+7)/(c-7):(c+7)/c=(c+7)/(c-7)*c/(c+7)=c/(c-7)
3)c/(c-7)+(5-c)/(c-7)=(c+5-c)/(c-7)=5/(c-7)