Odpowiedź:
1 bok - x
2 bok - x-20% = x-20/100 = x-2/10
3 bok x+40% = x+4/10
64 = x + x - 2/10x + x + 4/10x
64 = 3x +2/10x
64 = 3 1/5x | :3 1/5
20 = x
1 bok - 20
2 bok - 20 - (20 * 0,2) = 20 - 4 = 16
3 bok - 20 + (20 * 0,4) = 20 + 8 = 28
1 bok - 20
2 bok - 16
3 bok - 28
Szczegółowe wyjaśnienie:
obliczenia do 20 = x:
64 : 3 1/5 = 64/1 : 16/5 = 64/1 * 5/16 = 320/16 = 20