Question

помогите пожалуйста

Answer 1

( [ 1/ (a+4)  ]  +  [ (3a-5) / (a² -4a+16) ]  - [ (19a -68) / (a³+64) ] )  * [ (a²-16)/8]=
= [(1(a²-4a+4²)  + (3a-5)(a+4)  - (19a-68)) /  ((a+4)(a²-4a+4²)) ] * [(a²-16)/8]=
= [ (a²-4a+16 +3a²+12a-5a-20 -19a+68) / ((a+4)(a²-4a+16)) ] * [ (a²-16)/8 ]=
= [ (4a² -16a + 64 ) /((a+4)(a²-4a+16)) ]  *  [ (a²-16)/8]=
= [ (4(a²-4a+16)/ ((a+4)(a²-4a+16)) ]   *   [ (a²-4²) /8  ] =
= [4/ (a+4) ]  *  [ ((a-4)(a+4) )/8  ]=    (a-4)/2  =
= 1/2  *(a-4)  =  0.5(a-4) = 0.5a-2