Question

x+2y+9=0 and 3x+y-7=0 find the angle between the line

Answer 1

$x + 2y + 9 = 0 \\ 3x + y - 7 = 0 \\ multiply \: scond \: eqution \: by \: 2 \\ x + 2y + 9 = 0 \\ 6x + 2y - 14 = 0 \\ - 5x + 23 = 0 \\ 5x = 23 \\ x = 4.6$