Hi, thank you for posting your question here at Brainly.
Area of Triangle = 1/2baseheight
For triangle ABC:
144 = 1/2AC(3x+x)
2(144) = AC(4x)
AC = 72/x
Through ratio and proportion:
(3x+x)/AC = x/DE
4x/(72/x) = x/DE
4x^2/72 = x/DE
4x/72 = 1/DE
DE = 72/4x = 18/x
For triangle DBE:
A = 1/2baseheight
A = 1/2DEx
A = 1/2(18/x)x
A = 1/2*18
A = 9 square units
