Line rotated 90 degrees

[rajatmeh]

(B) for me as well.
I found it pretty simple..unless you guys expose me to some GMAT trick

[abhishek_mumbai]

equation is y = mx + b
and slope is m

if rotated by 90 degree, slope will be -1/m

if rotated by 180 degree , slope will be same. i.e. m

if parallel lines, slope is m.

[EbrahimHashem]

What if it was rotated 270 degrees instead of 90 degrees? what would the new slope be?

[Md. Minuddin]

Originally Posted by EbrahimHashem

What if it was rotated 270 degrees instead of 90 degrees? what would the new slope be?

Its slop will also be -1/m

[abhishek_mumbai]

rotation by 90, 270 will bring the line in perpendicular position and slope will be -1/m

rotate it by 180 , 360 or so.. it will be in same alignment. and slope will be m.

My turn now.. question..
what if I turn it to 55degree clockwise, 75 deg anticlockwise, 150 degree clockwise....

[madhur_ahuja]

Agree with B

[jayasankar]

The answe is -1/m
The given equation can be solved as y-2-b=mx + 2 => y = mx + (b+4)
The above equation is in the form y = mx +c where m is the slope

so the slope of the line perpendicular to this would be -1/m
As we know if m1 and m2 are the slopes of two lines perpendicular to each other the m1*m2=-1

[kranti_surya]

IMO B

(y+2-b)/x = (mx+2)/x
y = mx + b => Slope = m

Slopes of perpendicular lines are negative reciprocals of each other, so -1/m

[KrazyGMAT]

itna bolne k baad,,,OA to dedo yaaron!
It shud b B