Question

quanto e 10ab-[3ab-(ab+ab-5ab-5ab)-8ab] ?

Answer 1

10ab-[3ab-(ab+ab-5ab-5ab)-8ab] 
 = 10ab - [3ab - ab -ab + 5ab + 5ab] - 8ab] =
10ab - [ 3ab - ab - ab + 5ab + 5ab] - 8ab] =
10ab - 3ab + ab + ab - 5ab - 5ab + 8ab =
20ab - 13ab = 7ab

Resp: 7ab

Answer 2

10ab-[3ab - (ab+ab -5ab -5ab) -8ab]

10ab - [3ab - (2ab-10ab) - 8ab]

10ab - [3ab - (-8ab) - 8ab]

10ab - [ 3ab + 8ab -8ab]

10ab - 3ab

7ab