Question

find the value of the expression
$s^{2} \div (t \div 7) \div 4^{r}$
for $r = 2$, $s = 12$, and $t = 21$.

Explanation:

Step1: Substitute given values

Substitute $r=2$, $s=12$, $t=21$ into the expression:
$$12^2 \div (21 \div 7) \div 4^2$$

Step2: Calculate exponents first

Compute $12^2$ and $4^2$:
$$144 \div (21 \div 7) \div 16$$

Step3: Solve inner parentheses

Calculate $21 \div 7$:
$$144 \div 3 \div 16$$

Step4: Perform left-to-right division

First compute $144 \div 3$:
$$48 \div 16$$

Step5: Final division

Calculate $48 \div 16$:
$$3$$

Answer:

3