Odpowiedź :
1) x+(7+x)
----------------------
x+7+x
2x+7
---------------------------
2)2x+7=20
=========================
2x=20-7
2x=13
13/2=6,5
x=6,5
----------------------
x+7+x
2x+7
---------------------------
2)2x+7=20
=========================
2x=20-7
2x=13
13/2=6,5
x=6,5
0,5x + 3,5 + 0,5x = 20
x +3,5 = 20
x = 16,5
lub
x+(7+x)
______________=20 | *2
2
x+7+x = 40 |-7
2x = 33
x = 16,5
x +3,5 = 20
x = 16,5
lub
x+(7+x)
______________=20 | *2
2
x+7+x = 40 |-7
2x = 33
x = 16,5