If f(x) = 2x3 – 13x2 + 17x + 12, find (i) f (2) (ii) f (-3) (iii)

1.	If f(x) = 2x3 – 13x2 + 17x + 12, find (i) f (2) (ii) f (-3) (iii) f(0)
Answer» f(x) = 2x³ – 13x² + 17x + 12 (i) f(2) = 2(2)³ – 13(2)² + 17(2) + 12 = 2 x 8 – 13 x 4 + 17 x 2 + 12 = 16 – 52 + 34 + 12 = 62 – 52 = 10 (ii) f(-3) = 2(-3)³ – 13(-3)² + 17 x (-3) + 12 = 2 x (-27) – 13 x 9 + 17 x (-3) + 12 = -54 – 117 -51 + 12 = -222 + 12 = -210 (iii) f(0) = 2 x (0)³ – 13(0)² + 17 x 0 + 12 = 0 - 0 + 0 + 12 = 12

If f(x) = 2x3 – 13x2 + 17x + 12, find (i) f (2) (ii) f (-3) (iii) f(0)

Answer»

f(x) = 2x³ – 13x² + 17x + 12

(i) f(2) = 2(2)³ – 13(2)² + 17(2) + 12

= 2 x 8 – 13 x 4 + 17 x 2 + 12

= 16 – 52 + 34 + 12

= 62 – 52

= 10

(ii) f(-3) = 2(-3)³ – 13(-3)² + 17 x (-3) + 12

= 2 x (-27) – 13 x 9 + 17 x (-3) + 12

= -54 – 117 -51 + 12

= -222 + 12

= -210

(iii) f(0) = 2 x (0)³ – 13(0)² + 17 x 0 + 12

= 0 - 0 + 0 + 12

= 12