The Product Rule of Exponents states that when multiplying two expressions with the same base, you add the exponents.
In this case, you have \( (56)^3 \cdot (56)^{10} \).
Using the Product Rule: \[ (56)^3 \cdot (56)^{10} = (56)^{3 + 10} = (56)^{13} \]
Therefore, the exponent in the equivalent form is \( 13 \).