Final answer:
Without the specific expression provided, we cannot determine the value for the given variables. The process often involves substituting the known values into an algebraic equation and solving it, commonly using the quadratic formula for quadratic equations.
Step-by-step explanation:
The student has asked about the value of an expression given certain values for variables a, b, and c. However, the expression itself was not included in the question. To calculate the value of an expression, the specific formula or equation is required. For instance, if the expression was a quadratic equation of the form at² + bt + c = 0, one would use the quadratic formula to find the value, which is -b ± √(b² - 4ac) over 2a. Since the exact expression is missing in the question, we cannot determine its value without this information.
Expressions like these often appear in algebra and are common in mathematics education. Students typically encounter such problems in the context of solving quadratic equations, learning how variables interact within an equation, and understanding the roots or solutions of polynomials.