Question

The line passing through A(-2,3) and B(4,b) is perpendicular to the line 2x-4y=5. Find the value of b.

Answer 1

slope of A( -2,3) And B( 4,b)

is ( b-3)/ ( 4 -(-2))

b-3)/ 4+2

b-3)/6

Now as its perpendicular to 2x- 4y = 5

Slope of 2 x-4y = 5 is ( 2/4) = 1/2

Now if 2 lines are perpendicular having slope m1 and m2

then m1× m2 = -1

So

( b-3)/6. × 1/2 = -1

b-3)/6 = -2

b-3 = -12

b= -12 +3 = -9