A student has 20 pencils at the beginning of the school year. After a week, the student has 18 pencils left. If the student continues to use pencils at the same rate, which equation will represent pencils left after w weeks?

Answer: p = - 2w + 20

Step-by-step explanation:

If the student had 20 pencils but now has 18 pencils, he uses pencils at a rate of 2 per week. So, m = - 2 (negative because he is decreasing the amount of pencils). The student started with 20 pencils so b = 20

Use the y = mx + b but replace "y" with "p" and replace "x" with "w" and input the m and b as stated above:

p = - 2w + 20