How do you evaluate the expression 2x2+3x+9 if x=-3? Algebra Expressions, Equations, and Functions Variable Expressions 1 Answer smendyka Dec 6, 2016 18 Explanation: You substitute −3 for every occurrence of x in the expression and then calculate the result. Be sure to handle the signs of numbers correctly: 2(−32)+3(−3)+9→ (2⋅9)−9+9→ 18−0→ 18 Answer link Related questions How do you write the variable expression for: a quotient of 2 and the sum of a number and 3 ? What are variables? What are variable expressions? How do you write variable expressions? How do you evaluate variable expressions? How do you simplify the expression 3x−x+4? How do you write a quotient of a number and 6 as an expression? How do you evaluate the expression 2x+1 for x=1? How do you write a product of a number and 2 as an expression? How do you write 5 less than 2 times a number as a variable expression? See all questions in Variable Expressions Impact of this question 1903 views around the world You can reuse this answer Creative Commons License