Question

8)Calcule
a) +(--5mn)+(+7mn)=
b)+(+3x2y)+(-- 4x²y)=
c)+(+5x2 – 3xy + 4y2) + ( --4x2 + 5xy – 3y2)=
me ajudem por favor​

Answer 1

Resposta:

a) +(--5mn)+(+7mn)=

$- 5mn + 7mn \\ = 2mn$

b)+(+3x2y)+(-- 4x²y)

$3 {x}^{2} y - 4 {x}^{2} y \\ = - {x}^{2} y$

c)+(+5x2 – 3xy + 4y2) + ( --4x2 + 5xy – 3y2)

$5 {x}^{2} - 3xy + 4 {y}^{2} - 4 {x}^{2} + 5xy - 3 {y}^{2} \\ {x}^{2} + 2xy + {y}^{2}$