Final answer:
To simplify the expression, distribute the 5 to both terms inside the parentheses, combine like terms, and obtain the simplified expression 2x^2 + 23.
Step-by-step explanation:
To simplify the expression 7x2 + 3 - 5(x2 - 4), we can distribute the 5 to both terms inside the parentheses:
7x2 + 3 - 5x2 + 20
Combining like terms:
2x2 + 23
So, the simplified expression is 2x2 + 23.