Answer :

To evaluate the expression [tex]\( 8a^2 - 6a \)[/tex] when [tex]\( a = \frac{1}{2} \)[/tex], follow these steps:

1. Substitute [tex]\( a = \frac{1}{2} \)[/tex] into the expression:
[tex]\[ 8 \left( \frac{1}{2} \right)^2 - 6 \left( \frac{1}{2} \right) \][/tex]

2. Calculate [tex]\( \left( \frac{1}{2} \right)^2 \)[/tex]:
[tex]\[ \left( \frac{1}{2} \right)^2 = \frac{1}{4} \][/tex]

3. Multiply by 8:
[tex]\[ 8 \times \frac{1}{4} = 2 \][/tex]

4. Calculate [tex]\( 6 \times \frac{1}{2} \)[/tex]:
[tex]\[ 6 \times \frac{1}{2} = 3 \][/tex]

5. Substitute these values back into the expression:
[tex]\[ 2 - 3 \][/tex]

6. Perform the subtraction:
[tex]\[ 2 - 3 = -1 \][/tex]

So, when [tex]\( a = \frac{1}{2} \)[/tex], the value of the expression [tex]\( 8a^2 - 6a \)[/tex] is [tex]\(-1\)[/tex].