5×X-21:7=4+13 help plz

Răspuns :

5xX-21:7=4+13

5X-3=17

5X=17+3

5X=20

X=20:5

X=4

5 × x - 21 : 7 = 4 + 13

5 × x - 3 = 17

5 × x = 17 + 3

5 × x = 20

x = 20 : 5

x = 4

Reconstituire :

5 × 4 - 21 : 7 = 4 + 13

20 - 3 = 17

17 = 17