The first value is -9, so f(1)=-9. Next, to find the common difference, we subtract the second number from the first number, getting -2-(-9)=7. Therefore, the common difference is 7
<span>We know that 4 balls will make 8 caps. Than x balls will make 6 caps. We will use the proportion: 4 / 8 = x / 6. After that we will cross multiply: 8 x = 6 * 4, 8 x = 24, x = 24 : 8, x = 3. Answer: 3 balls of wills will make 6 knitted caps. I hope that my answer is helpful! Let me know if you need something more :)</span>
