1. Stating the problems: - Problem 8a: Solve for $a$ in the equation $8a = 0$. - Problem 8b: Solve for $b$ in the equation $8b = 0$. - Problem 9a: Solve for $a$ in the equation $9a = 0$. - Problem 9b: Solve for $b$ in the equation $9b = 0$. 2. Formula and rules: For equations of the form $ka = 0$ where $k$ is a constant, the solution is $a = 0$ because any number multiplied by zero equals zero. 3. Solving each: - For 8a: $8a = 0$ implies $a = \frac{0}{8}$. - Simplify: $a = \cancel{\frac{0}{8}}0$. - So, $a = 0$. - For 8b: $8b = 0$ implies $b = \frac{0}{8}$. - Simplify: $b = \cancel{\frac{0}{8}}0$. - So, $b = 0$. - For 9a: $9a = 0$ implies $a = \frac{0}{9}$. - Simplify: $a = \cancel{\frac{0}{9}}0$. - So, $a = 0$. - For 9b: $9b = 0$ implies $b = \frac{0}{9}$. - Simplify: $b = \cancel{\frac{0}{9}}0$. - So, $b = 0$. 4. Explanation: When a constant multiplied by a variable equals zero, the variable must be zero because zero times any number is zero. Dividing both sides by the constant isolates the variable. Final answers: - 8a: $a=0$ - 8b: $b=0$ - 9a: $a=0$ - 9b: $b=0$