Answer:

Step-by-step explanation:
we have

Solve for a
That means ----> Isolate the variable a
Factor 3 in the numerator right side

Simplify right side

subtract a both sides


subtract 1 both sides


Rewrite

Answer:
4.3
Step-by-step explanation:
6.8^2-5.3^2=x^2
AC=4.3