Answer:
1) n^2 – 3 n + 8 4^2 – 3*4 + 8 = 12
2) (x^2 – 4 y) / 2 (16 + 12) / 2 = 14
3) 4 * |-7 – 2| = 4 * 9 = 36 Abs -9 = 9
4) 19 – x^2 = 19 – 25 = -6 (-5)^2 = 25
5) S^2 t – 10 = -8^2 * ¾ -10 = 64 * ¾ - 10 = 38
6) 4 p^2 + 7 q^3 = 4 * 9 + 7 * (-8) = - 20 (-2)^3 = -8