Question

equation of the straight line

Answer 1

since 3x+y=4 and bx+2y+5 = 0 are parallel
slopes are equal so
-1/3=-2/b
b = 6
and since 3x+y=4 and x-ay+7 = 0 are perpendicular their product of slopes should be -1
-1/3*a/1 = -1
a = 3
hence a=3 and b=6