Answer:
3. x + 18.
4. 8n + 16
Explanation:
3. We have to calculate the area of wood present in the frame whose dimensions are given with the question.
Requires area = {(x + 3) × 1} + [(4 - 1) × {(x + 3) - (x - 2)}] = x + 3 + 3 × 5 = x + 18. (Answer)
4. The sum of four consecutive odd numbers where 2n + 1 is the smallest odd number will be
= (2n + 1) + (2n + 3) + (2n + 5) + (2n + 7)
= 8n + 16 (Answer)