I am assuming you wrote the problem wrong. Is it a^2?
A^2 -4A-21=0
(A-7)(A+3)=0
A=7 A=-3, ignore the negative number because it doesn't make sense if you plug in for a.
length=a+3=7+3=10
Width=7=a
Assuming that the center of each circle is at point C and D, then both have a radius of 7cm. We know that the formula for solving area of the circle is A=pi*r².
Then we solve area of once circle multiplied by two to get the total area of the given circles. The solution is shown below:
C1 area=3.1416*7²
C1 area=153.9384 cm²
Summation of the area of circle C and D is shown below:
Sum area=2*153.9384
Sum area=307.8768cm²
The answer is 98pi.
