Question:x = 5a + 7b + 9c, y = b - 3a - 4c, z = c - 2b + a.
ক. z থেকে a - c বিয়োগ কর ।
খ. দেখাও যে, x + y + z = 3(a + 2b + 2c)
গ. প্রমান কর যে, (x + y) - (a + 10b + 4c) = z
Answer ক. দেওয়া আছে, z = c - 2b + a
:. z - (a - c) = c - 2b + a - a + c = 2c - 2b
খ. দেওয়া আছে, x = 5a + 7b + 9c, y = b - 3a - 4c, z = c - 2b + a
x + y + z = (5a + 7b + 9c) + (b - 3a - 4c) + (c - 2b + a)
= 5a + 7b + 9c + b - 3a - 4c + c - 2b + a
= (5a - 3a + a) + (7b + b - 2b) + (9c - 4c + c)
= 3a + 6b + 6c
= 3 (a + 2b + 2c)
:. (x + y + z) = 3 (a + 2b + 2c)
গ. (x + y) - (a + 10b + 4c)
= (5a + 7b + 9c) + (b - 3a - 4c) - (a + 10b + 4c)
= 5a + 7b + 9c + b - 3a - 4c - a - 10b - 4c
= (5a - a - 3a) + (7b + b - 10b) + (9c - 4c - 4c)
= a - 2b + c = c - 2b + a = z
:. (x + y) - (a + 10b + 4c) = z