Question 125699
the following graph shows the enrollment at a community college:

{{{1997- 6000}}}
{{{1998- 8000}}}
{{{1999- 10000}}}
{{{2000- 12000}}}
{{{2001- 14000}}}

as you can see, the difference between each two consecutive years is {{{2000}}}, so the increase in enrollment {{{y}}} from {{{x1}}} to {{{x2}}} year will be equal to the sum of prodct {{{2000}}}times the difference between each two years (in your case {{{1997}}} and {{{2001}}}) and the number of enrolled students in {{{1997}}}:

{{{y= 2000(x2-x1) + 6000}}}

from {{{1997}}} to {{{2001}}} will be

{{{y= 2000(2001-1997) + 6000}}}

{{{y= 2000(4) + 6000}}}

{{{y= 8000 + 6000}}}

{{{y= 14000}}}

the increase in enrollment from {{{1997}}} to {{{2001}}} is {{{8000}}}

or, you can simply find it this way:

if the increase in enrollment from {{{1997}}} to {{{2001}}} is {{{y}}},the number of enrolled students in {{{1997}}} is {{{x1}}} and the number of enrolled students in {{{2001}}} is {{{x2}}}, then:

{{{y = x2 -x1}}}

{{{y = 14000 -6000}}}

{{{y=8000}}}