1. **Problem Statement:** Find the market equilibrium price and quantity given the demand equation $p - 3q = 22$ and the supply equation $q^2 + 2p + 4q = 100$, where $p$ is price and $q$ is quantity.
2. **Step 1: Express $p$ from the demand equation.**
From $p - 3q = 22$, we get:
$$p = 3q + 22$$
3. **Step 2: Substitute $p$ into the supply equation.**
Supply equation: $q^2 + 2p + 4q = 100$
Substitute $p = 3q + 22$:
$$q^2 + 2(3q + 22) + 4q = 100$$
Simplify:
$$q^2 + 6q + 44 + 4q = 100$$
$$q^2 + 10q + 44 = 100$$
4. **Step 3: Rearrange to form a quadratic equation.**
$$q^2 + 10q + 44 - 100 = 0$$
$$q^2 + 10q - 56 = 0$$
5. **Step 4: Solve the quadratic equation using the quadratic formula:**
$$q = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=1$, $b=10$, $c=-56$.
Calculate discriminant:
$$\Delta = 10^2 - 4(1)(-56) = 100 + 224 = 324$$
Square root:
$$\sqrt{324} = 18$$
Calculate roots:
$$q = \frac{-10 \pm 18}{2}$$
Two solutions:
$$q_1 = \frac{-10 + 18}{2} = \frac{8}{2} = 4$$
$$q_2 = \frac{-10 - 18}{2} = \frac{-28}{2} = -14$$
Since quantity cannot be negative, $q = 4$.
6. **Step 5: Find equilibrium price $p$ using $p = 3q + 22$.**
$$p = 3(4) + 22 = 12 + 22 = 34$$
7. **Step 6: Calculate total revenue (TR).**
Total revenue is price times quantity:
$$TR = p \times q = 34 \times 4 = 136$$
**Final answers:**
- Market equilibrium quantity: $4$
- Market equilibrium price: $34$
- Total revenue: $136$
Market Equilibrium Ec31A8
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