jmc

The total area of the rectangle is $3\times 4=12$.

The total area of the shaded regions equals the total area of the rectangle (12) minus the area of the unshaded region.

The unshaded region is a triangle with base of length 1 and height 4; the area of this region is $\frac{1}{2}(1)(4)=2$.

Therefore, the total area of the shaded regions is $12-2=\boxed{10}$.