3) Efetue:
a) (+1/2x) + (–1/3x) = b) (–2/5x) + (–2/3x) = c) (–7/2y) + (+1/4y) =
d) (+2m) +(–3/4m) = e) (+2/3x) – (–3/2x) = f) (–3/4y) – (+1/2y) =
g) (+2/5m) – (+2/3m) = h) (–3x) –(–2/5x) =
preciso dos cálculos!!
Soluções para a tarefa
3) Efetue:
SOMA com FRAÇÃO faz mmc ( EM todos)
a) (+1/2x) + (–1/3x) = mesmo que
1x 1x
-------- - --------
2 3 ( 2 e 3 números primos ) mmc =2x3 = 6
3(1x) - 2(1x)
---------------------------
6
3x - 2x 1x x
----------- = ------------- mesmo que -----------
6 6 6
b) (–2/5x) + (–2/3x) =
c) (–7/2y) + (+1/4y) = idem acima
7y 1y
- --------- + ---------
2 4 ( 4 é multiplo de 2) mmc = 4
-2(7y) + 1(1y)
-------------------------------
4
- 14y + 1y - 13y 13y
--------------- = ------------- = - ---------- mesmo que = - 13/4y
4 4 4
d) (+2m) +(–3/4m) =
3m
2m - ----------- mmc = 4
4
4(2m) - 1(3m) 8m - 3m 5m
------------------- = ------------------ = ----------- = 5/4m
4 4 4
e) (+2/3x) – (–3/2x) = veja o SINAL (-)(-) = +
(+2/3x) + (3/2x)
2x 3x
------ + ------------ (mmc = 2x3 = 6) idem no (a))
3 2
2(2x) + 3(3x) 4x + 9x 13x
---------------------------= ----------------- = ----------- = 13/6x
6 6 6
f) (–3/4y) – (+1/2y) =
3y 1y
- ------- - ---------
4 2 ( 4 é multiplo de 2) mmc = 4
-1(3y) - 2(1y) - 3y - 2y - 5y
----------------- = ----------------- = ------------- = - 5/4y
4 4 4
g) (+2/5m) – (+2/3m) =
2m 2m
----------- - ------------
5 3 ( 5 e 3 são primos) mmc = 5x3 = 15
3(2m ) - 5(2m) 6m - 10m - 4m
--------------------------- = ----------------------- = ------------ = - 4/15m
15 15 15
h) (–3x) –(–2/5x) = olha o sinal (-)(-) = +
2x
- 3x + ---------- mmc = 5
5
5(-3x) + 1(2x) - 15x + 2x - 13x
-------------------------- = ------------------ = ------------- = - 13/5x
5 5 5