the point-slope line equation . where m is the slope.
First find the slope of the line.
\ (Substitute
2 for x1,
1 for y1, 1 for x2 and 2 for y2)
(Product of two same signs is positive) \ \
(Add:
)
(Cancel common terms)
Next find the point-slope line equation .
(Substitute
2 for x1,
1 for y1and
)
(Product of two same signs is positive)
(Distributive property:
)
(Multiply:
)
(Subtract 1 from each side)
(Additive inverse proeprty:
)
(Additive identity proeprty:
)
(Subtract:
)
The point-slope line equation is .