Answer:
Step-by-step explanation:
3x (4x – 5) + 3
3x (4x – 5) + 3 = (3x × 4x) – (3x × 5) + 3
3x (4x – 5) + 3 = 12x2 – 15x + 3
Substitute the value of (i) x = 3 in 12x2 – 15x + 3
12x2 – 15x + 3
Put x = 3
⇒ 12 × (32) – (15 × 3) + 3
⇒ 12 × 9 – 45 + 3
⇒ 108 – 45 + 3
⇒ 66
Substitute the value of (ii) x =1/2 in 12x2 – 15x + 3
12x2 – 15x + 3
Put = 1/2
⇒ 12 × (1/2)2 – (15 × 1/2) + 3
⇒ 12 × 1/4 – (15 × 1/2) + 3
⇒ 3 – 15/2 + 3
⇒ 6 – 15/2
⇒ (12 – 15)/2
⇒ -3/2
