Iti voi explica cum tu poti rezolva toate exercitiile la fel cum am facut eu.
Avem de exemplu:
Daca e plus, facem asa:
a + b = c
a = c - b
Daca e minus, facem asa:
a - b = c
a = c + b
Daca e inmultit, facem asa:
a x b = c
a = c : b
Daca e impartit, facem asa:
a : b = c
a = c x b
Mai be scurt, dincolo de egal, trecem numarul cu SENS OPUS.
[tex]+[/tex] devine —
— devine [tex]+[/tex]
x devine :
: devine x
D. ( x : 2 ) x 3 = 30 x 3
( x : 2 ) x 3 = 90
( x : 2 ) = 90 : 3
( x : 2 ) = 30
x = 30 x 2
x = 60
I. 81 + 9 : 9 x ( x + 7 ) = 101
81 + 9 : 9 x x = 101 - 7
81 + 9 : 9 x x = 94
81 + 1 x x = 94
81 + x = 94
x = 94 - 81
x = 13
