Question

1)Calcule:
A)(3a2-5ab+2c-2bc)-(5a2-5ab-2bc)
B)(3y2/2-3y-2)+(2y2/3+1/4+1/2)
C)(x/2-3xy/4+y/3)-(3y/2-xy/3-2x)

Answer 1

a) (3a²-5ab+2c-2bc) - (5a²-5ab-2bc)
= 3a²*-5ab+2c*-2bc-5a²*+5ab*+2bc *elimine os opostos* *some os demais*
= -2a² + 2c

b)(3y²/2-3y-2) + (2y²/3+1/4+1/2)
= 3y²/2-3y-2 + *(2y²/3+3/4) *quando existe um "+" antes do parêntese a expressão se mantem a mesma*
= 3y²/2-3y-2 + 2y²/3+3/4
= 13/6 y² - 3y - 5/4

c)(x/2-3xy/4+y/3)-(3y/2-xy/3-2x)
= x/2-3xy/4+y/3-3y/2+xy/3+2x
= 5/2 x - 5/12 xy - 7/6 y