Evaluate Expressions
1. **State the problem:**
We are given $a=5$, $b=-2$, and $c=-3$.
We need to find:
(i) $5abc - a^2c$
(ii) $5b^2 - 3a - 2c$
2. **Calculate (i) $5abc - a^2c$:**
First, calculate each component:
$$abc = 5 \times (-2) \times (-3) = 5 \times 6 = 30$$
Then:
$$5abc = 5 \times 30 = 150$$
Next, calculate $a^2c$:
$$a^2 = 5^2 = 25$$
$$a^2c = 25 \times (-3) = -75$$
Now substitute these values into the expression:
$$5abc - a^2c = 150 - (-75) = 150 + 75 = 225$$
3. **Calculate (ii) $5b^2 - 3a - 2c$:**
Calculate $b^2$:
$$b^2 = (-2)^2 = 4$$
Multiply by 5:
$$5b^2 = 5 \times 4 = 20$$
Calculate $-3a$:
$$-3a = -3 \times 5 = -15$$
Calculate $-2c$:
$$-2c = -2 \times (-3) = 6$$
Now sum all terms:
$$5b^2 - 3a - 2c = 20 - 15 + 6 = 11$$
**Final answers:**
(i) $5abc - a^2c = 225$
(ii) $5b^2 - 3a - 2c = 11$