Question

What is an equation of the line that passes through the point (7, -7) and is

perpendicular to the line x – 2y = 2?

Answer 1

set two equation of line y=ax+b and y=cx+d

when these two lines are perpendicular to each other, then a*c=(-1)

x-2y=2

=>x-2=2y

=>(1/2)x-1=y

set the answer is y=ax+b

we can know that a/(1/2)=(-1)

=>a=-2

bring a=-2 and(7,-7) in y=ax+b

-7=(-2)*7+b

=>b=7

the answer is y=-2x+7