12. evaluate xyz² if x = -2, y = 7, and z = -4. (example 6)

Explanation:

Step1: Substitute the values

Substitute $x = - 2$, $y = 7$, and $z=-4$ into $xyz^{2}$. We get $(-2)\times7\times(-4)^{2}$.

Step2: Calculate $(-4)^{2}$

$(-4)^{2}=(-4)\times(-4) = 16$. So the expression becomes $(-2)\times7\times16$.

Step3: Multiply the numbers

$(-2)\times7=-14$, then $-14\times16=-224$.

Answer:

$-224$