Solve the following: Find the acute angle between lines having slopes 3 and `-2`

Solve the following:If the angle between two lines in 45^o and the slope of one of the line is 1/2 ,find the slope of the other line.

The acute angle between the lines having direction ratios 5,4,1 and -3,2,1 is

Find the acute angle between the pairs of lines x+3y+5=0 and 2x+y-1=0

Answer the following question.Find the equation of the line having slope of 5 and containing point A(-1,2)

Select and write the correct answer from the given alternatives in each of the following:The acute angle between the lines y=2x and y=-2x is