Answer:
x=7.78
Step-by-step explanation:
142=10x+8x+2
Move all numbers with the same variables to each side to separate them.
142-2=10x+8x
140=18x
Divide by 18.
x= 140/18
area = L x W
area = 72
L=18
72= 18 x w
w=72/18 = 4
width is 4 cm