Answer:
The length is 5 cm and the width is 4 cm
Explanation:
I assume that is a rectangle
Let
x----> the length of rectangle
y ---> the width of rectangle
we know that
The area of rectangle is
A=xy
A=20 cm²
so
20=xy -----> equation A
The perimeter of rectangle is
P=2(x+y)
P=18 cm
so
18=2(x+y)
9=x+y -----> y=9-x ----> equation B
Substitute equation B in equation A and solve for x
20=x(9-x)
20=9x-x²
x²-9x+20=0
Solve the quadratic equation by graphing
The solution is x=5 cm (I assume that the length is greater than the width)
see the attached figure
Find the value of y
y=9-5=4 cm
therefore
The length is 5 cm
The width is 4 cm