2.1 Evaluate the following algebraic expression for the given values. $\frac{1}{2} b h$, for $b=7$ and $h=5$ The value of the expression $\frac{1}{2} b h$, for $b=7$ and $h=5$ is (Type an integer or a decimal.)

Step 1 ：Given the algebraic expression \(\frac{1}{2} b h\), where \(b=7\) and \(h=5\).

Step 2 ：Substitute the given values into the expression, we get \(\frac{1}{2} * 7 * 5\).

Step 3 ：Simplify the expression to get the final result.

Step 4 ：Final Answer: The value of the expression \(\frac{1}{2} b h\), for \(b=7\) and \(h=5\) is \(\boxed{17.5}\).