evaluate (7j + 5 - 8k) when (j = 0.5) and (k = 0.25).

Explanation:

Step1: Substitute values

Substitute $j = 0.5$ and $k=0.25$ into $7j + 5-8k$. $7\times0.5 + 5-8\times0.25$

Step2: Calculate multiplications

Calculate $7\times0.5$ and $8\times0.25$. $7\times0.5=3.5$, $8\times0.25 = 2$. So the expression becomes $3.5 + 5-2$.

Step3: Calculate addition and subtraction

First add $3.5$ and $5$: $3.5+5 = 8.5$. Then subtract $2$ from $8.5$: $8.5 - 2=6.5$.

Answer:

$6.5$