Evaluate with a Variable the Composition of Two Functions

The video tutorial explains how to solve a mathematical problem involving the function H of X, which is defined as X^2 + 6X + 8. The instructor demonstrates how to substitute 3A into the function to find H of 3A, and then further simplifies the expression. The process involves substituting H of 3A into another function, F of X = 5X, and applying the distributive property to reach the final answer. The tutorial emphasizes understanding the substitution process and simplification techniques.

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