Which expression is equivalent to (5x^3)(2x^7)?

The expression (5x^3)(2x^7) can be simplified by multiplying the coefficients (the numbers outside of the variables) together and adding the exponents of the same variable.

In this case, the coefficient 5 and 2 multiply to give 10.

The variable x has an exponent of 3 in the first term and 7 in the second term. Adding these exponents together gives x^(3+7) = x^10.

Therefore, the simplified expression is 10x^10.