Page 58 - E booklet prep 3 bader 2025 b_Neat
P. 58
Relations between slopes of the straight lines:
First : two parallel straight lines
the slope of the straight line = the slope of any parallel straight line to it
???? // ???? ? ???? = ????
second : two perpendicular straight lines
-??
the slope of the straight line = ?????? ?????????? ???? ?????? ?????????????????????????? ???????? ???? ????
???? ? ???? ? ???? × ???? = -?? , [???? ? ??*, ???? ? ??*
Examples:
1) Prove that the straight line passing through the two points ( ?? , ?? ) , (?? , ??)
is parallel to the straight line passing through the two points ( -?? , ?? ) , (?? , ??)
M1 = ??-?? = ??
??-?? ??
M2 = ??-?? = ?? M1 // M2
??-(-??) ??
They are parallel
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