IV. Find the value of each expression if: a = 1, b = -1, c = 2, x= -2, y = 1, z = 0.

1. 3x³ + 7y² — 4z

2. 8ab + 3bc — 12

3. 3c — 5z²

4. 16(a — b)² + 9(x + y)²

5.
[tex] \frac{bc}{3} + \frac{a}{xy} + \frac{3}{ab} [/tex]
6.
[tex] \frac{3a \: - \: 7b}{2a \: + \:6b } [/tex]
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