1. **State the problem:** We are given a table of values for an exponential function and Tegan's proposed equation $y=5(0.25)^x$. We need to verify if this equation correctly represents the data. 2. **Recall the general form of an exponential function:** $$y = a b^x$$ where $a$ is the initial value (when $x=0$) and $b$ is the base or growth/decay factor. 3. **Identify $a$ from the table:** When $x=0$, $y=5$. So, $a=5$. 4. **Check Tegan's $a$-value:** Tegan's equation has $a=5$, which matches the table. So the $a$-value is correct. 5. **Find the $b$-value from the table:** Use two points to find $b$. For example, from $x=0$ to $x=1$: $$b = \frac{y_1}{y_0} = \frac{20}{5} = 4$$ 6. **Check if $b=0.25$ as Tegan says:** Tegan's equation uses $b=0.25$, but from the table, $b=4$. 7. **Verify with other points:** From $x=1$ to $x=2$: $$\frac{80}{20} = 4$$ which confirms $b=4$ consistently. 8. **Conclusion:** - Tegan's $a$-value is correct. - Tegan's $b$-value is incorrect; it should be 4, not 0.25. 9. **Answer to the options:** - "The a-value in Tegan's equation is correct." is true. - "The b-value in Tegan's equation is wrong." is true. Therefore, two of these apply: the correct $a$-value and the incorrect $b$-value. **Final equation:** $$y = 5 \times 4^x$$