perpendicular linees have slopes that multiply to -1
paralell lines have slopes that are the same
also
for ax+by=c
the slope is -a/b
so
10x - 5y = 8? slope is -10/-5=2, paralell so slope of parallell line is also 2 (B)
4x + 2y = 5? slope is -4/2=-2, paralell so slope of paralell line is also -2 (E)
x - 3y = 9? slope is -1/-3=1/3, perpendicular, so 1/3 times -3=-1 (C)
x - 5y = -10? slope is -1/-5=1/5, perpendicular, so 1/5 times -5=-1 (A)
4x + y = -1? slope is -4/1=-4, parallel so -4 (D)
What is the slope of a line parallel to 10x - 5y = 8? B
What is the slope of a line parallel to 4x + 2y = 5? E
What is the slope of a line perpendicular to x - 3y = 9? C
What is the slope of a line perpendicular to x - 5y = -10? A
What is the slope of a line parallel to 4x + y = -1? D