Find the equation of the straight line passing through (-1, 2) and whose slope is $\dfrac{2}{5}.$

The equation of line with slope m and passing through point (x₁, y₁) is given by

y - y₁ = m(x - x₁)

Putting values we get,

$\Rightarrow y - 2 = \dfrac{2}{5}(x - (-1)) \\[1em] \Rightarrow 5(y - 2) = 2(x + 1) \\[1em] \Rightarrow 5y - 10 = 2x + 2 \\[1em] \Rightarrow 2x - 5y + 2 + 10 = 0 \\[1em] \Rightarrow 2x - 5y + 12 = 0.$

Hence, the equation of the line is 2x - 5y + 12 = 0.