What is the explanation for 10x plus 7 plus 3x?

The expression 10x + 7 + 3x can be simplified by combining like terms. Like terms are terms that have the same variable raised to the same power. In this case, the like terms are 10x and 3x, as they both have the variable x raised to the power of 1. Combining these like terms gives us 13x. Therefore, the simplified expression is 13x + 7.