Any line passing through the intersection of the given lines is x+3y+4+λ(3x+y+4) = 0 ........ (i) Or, (1+3λ)x+(3+λ)y+4(1+λ) = 0 The slope of the line m = - 1+3λ/3+λ As the line is equally inclined with the axes, m = tan 45° or tan 135° = ±1 ∴ - 1+3λ/3+λ = ±1, > λ = ±1 ∴ The required lines are (putting λ = - 1, 1 in (i)) x+ 3y + 4 ± (3x+y+4) = 0 Or, x + y + 2 = 0 and x - y = 0