Simplify by combining like terms: 2x squared + 3x + 7 + x squared + 4x + 5.

1. Group the like terms together: the x squared terms, the x terms, and the constant terms. 2. Combine the x squared terms: 2x squared plus x squared equals 3x squared. 3. Combine the x terms: 3x plus 4x equals 7x. 4. Combine the constants: 7 plus 5 equals 12. 5. Putting the groups back together gives 3x squared plus 7x plus 12. _Source: OpenStax Elementary Algebra (CC BY 4.0), Ch 1 "Foundations", section 1.2 Use the Language of Algebra_