Solution:
$$\eqalign{
& 2x + 5y = 12 \cr
& x{\text{ - axis}}:y = 0\,;\,x = 6 \cr
& x + y = 3 \cr
& x{\text{ - axis}}:y = 0\,;\,x = 3 \cr
& 2x + 5y = 12\,\,\,\,\,*1 \cr
& \underline {\,x + y = 3\,\,\,\,\,\,\,\,\,\,\,\,*2\,} \cr
& \,\,\,\,\,2x + 5y = 12 \cr
& \,\,\,\,\,2x + 2y = 6 \cr
& \underline {\,\, - \,\,\,\,\,\, - \,\,\,\,\,\,\,\, - \,\,\,\,} \cr
& \,\,\,\,\,3y = 6 \cr
& \,\,\,\,\,\,y = 2 \cr
& \,\,\,\,\,\,x = 3 - 2 = 1 \cr} $$
$$\eqalign{
& {\text{Area of traingle}} = \frac{1}{2} \times {\text{base}} \times {\text{height}} \cr
& = \frac{1}{2} \times 3 \times 2 \cr
& = 3 \cr} $$