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

Step-by-step 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

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