A teacher buys 100 pencils to keep in her classroom at the beginning of the school year. She allows the students to borrow pencils, but they are not always returned. On average, she loses about 8 pencils a month. Write an equation in slope-intercept form that represents the number of pencils she has left y after a number of x months.

Step-by-step explanation:

The number of pencils at the beginning of the school year is 100. Since the pencils which she allowed the students to borrow is not usually returned. The rate at which she loses the pencils per month would constant. So the slope of the graph if number of pencils is plotted on the y axis and the months on the x axis,

The slope, m would be - 8 pencils per month because it is reducing

The equation for slope intercept form is expressed as

y = mx + c

Where

c = intercept

To determine c, we would substitute y = 100, x = 0 and m = 8 into the slope intercept equation. Ut becomes

100 = - 8*0 + c

c = 100

The equation becomes

y = - 8x + 100