Respuesta :

Answer:

a=16

Step-by-step explanation:

a*2+ 12*2 = 20*2

12to the power of 2 is 144

20to the power of 2 is 400

a*2+ 144 =400

-144. -144

a*2= 256

find the square root of 256 which is 16

so there for 16 is the answer

a=16