<PRE><B>Question 664366</B>
we will take two points and find equation of a line passing through

let points be ({{{1}}},{{{1}}}), and ({{{3}}},{{{7}}})


*[invoke find_equation_of_line 1, 1, 3, 7]

so, equation is:

{{{y=3x -2}}}....and the slope of this line is positive, {{{m=3}}} 

now check if all points lie on same line:

{{{drawing(600,600,-10,10,-10,10,circle(1,1,0.2),circle(2,4,0.2),circle(3,7,0.2),circle(0,0,0.0),graph(600,600,-10,10,-10,10,3x -2))}}}


as you can see,  all points do lie on same line


now we can calculate {{{y}}} if {{{x=4}}} using {{{y=3x -2}}}:


{{{y=3*4 -2}}}

{{{y=12 -2}}}

{{{y=10}}}..........the missing value

so, your table is:

x|	y
1|	1
2|	4
3|	7
4|	10


now check if a point ({{{4}}},{{{10}}}) also lie on a line


{{{drawing(600,600,-10,10,-10,15,grid(1),circle(1,1,0.2),circle(2,4,0.2),circle(3,7,0.2),circle(4,10,0.2),graph(600,600,-10,10,-10,15,3x -2))}}}

-correlation would be {{{100}}}% because every point fit on the line


</PRE>