Respuesta :

[tex]1+2a-3(4+5a)+6(7-8a) =1+2a-12-15a+6(7-8a) =1+2a-12-15a+42-48a =-61a+31 [/tex]
Hope this helps:)

Answer:

31 - 61a

Step-by-step explanation:

We distribute, being especially careful with the negative signs: 

1 + 2a - 3(4 + 5a) + 6(7 - 8a)

1 + 2a - 3 * 4 - 3 * 5a + 6 * 7 - 6 * 8a

1 + 2a - 12 - 15a + 42 - 48a

31 - 61a