SOLUTION: A line passes through (9, –9) and (10, –5).Write an equation for the line in point-slope form. Rewrite the equation in standard form using integers. Help please!!!

Algebra ->  Linear-equations -> SOLUTION: A line passes through (9, –9) and (10, –5).Write an equation for the line in point-slope form. Rewrite the equation in standard form using integers. Help please!!!      Log On


   

Question 700344: A line passes through (9, –9) and (10, –5).Write an equation for the line in point-slope form.
Rewrite the equation in standard form using integers. Help please!!!
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
P1 ( 9,-9 )
P2( 10,-5 )
The slope is ( change in y ) / ( change in x )
+%28+-9+-%28-5%29+%29+%2F+%28+9+-+10+%29+=+-4+%2F+%28-1%29+
+-4+%2F+%28-1%29+=+4+
------------------
Now I can use either of the points and the slope
in the general point-slope formula
+%28+y+-%28-5%29+%29+%2F+%28+x+-+10+%29+=+4+
+%28+y+%2B+5+%29+%2F+%28+x+-+10+%29+=+4+
+y+%2B+5+=++4%2A%28+x+-+10+%29+
+y+%2B+5+=+4x+-+40+
+y+=+4x+-+45+
In standard form,
+4x+-+y+=+45+
-----------------
check:
Does it go through ( 10, -5 ) ?
+4x+-+y+=+45+
+4%2A10+%2B+5+=+45+
+40+%2B+5+=+45+
+45+=+45+
OK
Does it go through ( 9,-9 ) ?
+4%2A9+-%28-9%29+=+45+
+36+%2B+9+=+45+
+45+=+45+
OK