This looks like "half" a property. I'm assuming you mean something that looks like this:
IF a + b = a + c, THEN b = c. In the expression in your problem, the role of a is being played by 7. The role of b is played by (4 + 6), and the role of c is played by n.
The conclusion would be that 4 + 6 = n.
But you asked about what the property is called. The likely name is the subtraction property of equality. How did we go from a + b = a + c to the conclusion b = c? We subtracted a from both sides of the equation.
Answer:

Step-by-step explanation:

<span>A = P(1+r/2)^2t
A/P = (1+r/2)^2t
ln(A/P) = 2t ln((1+r/2))
ln(A/P)/ln(1+r/2) =2t
ln(9000/4190.51)/ln(1+0.052/2)=2t
t=15 yrs
therfore ans is C.14 years ,11 months</span>
--Answer--
It's in the picture, desmos will help for graphing.