Final answer:
The phrase 'twice the sum of a number and 3' translates to the mathematical expression '2(x + 3)', which simplifies to '2x + 6'.
Step-by-step explanation:
The phrase 'twice the sum of a number and 3' can be expressed as a mathematical expression. Firstly, you interpret the sum of a number and 3, which can be written as 'x + 3', where 'x' represents the unknown number. To find twice this sum, you simply multiply by 2, resulting in the expression '2(x + 3)'. This expression can be further simplified, if needed, to '2x + 6', by using the distributive property, where you multiply 2 by both 'x' and 3.