Answer:
Step-by-step explanation:
Is there any sign of addition or subtraction between (c + 3d) and (c - d) or we have to just multiply
If we have to multiply then
2(c + 3d) (c - d)
= 2(c2 - cd + 3cd - 3d2)
= 2(c2 + 2cd - 3d2)
= 2c2 + 4cd - 6d2