1. Zadatak

Prvo rješenje.

$$135 + 5 + l = 147$$ $$l = 7$$ $$j + 104 + 8 = 147$$ $$j = 35$$ $$35 + s + 5 + 7 = 147$$ $$s = 100$$ $$100 + z = 104$$ $$z = 4$$ $$4 + p = 5$$ $$p = 1$$

Lisica ima $7$ kg, jelen $35$ kg, vepar $100$ kg, zeko $4$ kg, a ptica (fazan) $1$ kg.

$$35 + 4 + 7 = 46\ \text{kg}$$

Lisica, zeko i jelen zajedno imaju $46$ kg.

Drugo rješenje.

Označimo s $j$ masu jelena, sa $s$ masu svinje, sa $z$ masu zeca, s $p$ masu ptice i s $l$ masu lisice u kilogramima.

Tada vrijedi:

$$\begin{aligned} j+s+z+p+l &= 147,\\ j+s &= 135,\\ z+p &= 5,\\ p+l &= 8,\\ s+z &= 104. \end{aligned}$$

Uvrstimo:

$$\begin{aligned} j+s+z+p+l &= 147,\\ 135+5+l &= 147,\\ l &= 147-135-5,\\ l &= 7. \end{aligned}$$ $$\begin{aligned} j+104+8 &= 147,\\ j &= 147-104-8,\\ j &= 35. \end{aligned}$$ $$\begin{aligned} 35+s+5+7 &= 147,\\ s &= 147-35-5-7,\\ s &= 100. \end{aligned}$$ $$\begin{aligned} 100+z &= 104,\\ z &= 104-100,\\ z &= 4. \end{aligned}$$ $$\begin{aligned} 4+p &= 5,\\ p &= 1. \end{aligned}$$

Lisica ima $7$ kg, jelen $35$ kg, vepar $100$ kg, zeko $4$ kg, a fazan $1$ kg.

$$j+z+l=35+4+7=46\ \text{kg}.$$

Lisica, zeko i jelen zajedno imaju $46$ kg.