It is known that 5A + 4 and 3a-4 are the square roots of the same number. Try to find the value of A A is 0 absolutely true, but is a - 4 true?

It is known that 5A + 4 and 3a-4 are the square roots of the same number. Try to find the value of A A is 0 absolutely true, but is a - 4 true?

5a+4=3a-4
a=-4
5a+4=-(3a-4)
a=0