Question

the lines y=2x-1 and y=ax+2 are perpendicular if a=

Answer 1

a would have to equal the opposite reciprocal, which is -1/2

Answer 2

  solution

if y=2x-1    and  y=ax+2    

 mathematically -1/2=-1/a

 a=2  ⇒

when a=2  ⇒the two lines are perpendicular