Verified answer

Explicação passo-a-passo:

a) 7x +2x - x -3x +5x=

14x - 4x =

+10x

b) 5y² - ( +3y²) +( -12y² +9y²)=

5y² -3y² + (-3y²)=

5y² -3y² -3y²=

5y² -6y²=

- 1y²

c) 10ab - [ 3ab - ( 3ab -5ab) - 8ab]=

10ab - [ 3ab - ( - 2ab) -8ab]=

10ab - [ 3ab +2ab -8ab]=

10ab - [ 5ab - 8ab]=

10ab - [ - 3ab]=

10ab + 3ab =

13ab

d) 2xy + [ -5xy +2xy - (5xy -2xy) - 8xy]=

2xy + [ -3xy - ( +3xy) - 8xy]=

2xy + [ -3xy - 3xy - 8xy]=

2xy + [ - 14xy]=

2xy - 14xy=

- 12xy