.
b + h = 14, (1) ("The base and height of a triangle total 14 cm")
= 20 (2) "(the area is 20 cm2")
=====>
b + h = 14,
b*h = 40.
From this point, you can find the solution mentally and momentarily.
There are two sets of solutions:
1) b = 10, h = 4, and
2) b = 4, h = 10.
Notice that the question is formulated INCORRECTLY.
We can not find the dimensions of the triangle without additional info.
Based on the given info, we can only find the base and the height of the triangle.