Question

find the equation of a line passes through point 2,1 and the acute angle subtend by it and the line 4+y=0 equal to 45 degree​

Answer 1

Explanation:

let an equation of this line : y= ax+b ....a : is the slope

1) the acute angle subtend by it and the line 4+y=0 equal to 45 degree​

so : a = tan (45°) =1

so : y = x+b

calculate : b this line passes through point A(2,1) : 1= 2+b

b= - 1

conclusion : y = x -1 color : red 4+y =0 color : bleue

look this graph