1. **Identify the type of relation given the set of points**: $\{(1,1), (2,2), (3,3), (-1,4), (5,5)\}$. - A function assigns exactly one output for each input. - Check if any input (x-value) repeats with different outputs (y-values). - Inputs are 1, 2, 3, -1, 5, all unique. - Therefore, this is a function. - Check if it is one-to-one: each output must also be unique. - Outputs are 1, 2, 3, 4, 5, all unique. - So, it is a one-to-one function. **Answer:** A. One to one Function 2. **Identify the type of sequence:** $39, 30, 21, 12, 3, -6, -15$ - Check if arithmetic: difference between terms is constant. - Differences: $30-39 = -9$, $21-30 = -9$, $12-21 = -9$, $3-12 = -9$, $-6-3 = -9$, $-15-(-6) = -9$ - The common difference is $-9$, so it is an arithmetic sequence. - Check if geometric: ratio between terms is constant. - Ratios: $\frac{30}{39} \neq \frac{21}{30}$, so not geometric. - Fibonacci sequence is sum of previous two terms, which this is not. **Answer:** A. Arithmetic Sequence