Question

Use any method to multiply (3a + 2b – c)(a – b + 2c).

Answer 1

Answer:

A)

3a2 – 2b2 – 2c2 – ab + 5ac + 5bc

$(3a + 2b - c)(a - b + 2c) \\ = (3 {a}^{2} - 3ab + 6ac + 2ab - 2 {b}^{2} + 6bc - ac + bc - 2 {c}^{2} ) \\ = 3 {a}^{2} - ab + 5ac - 2 {b}^{2} + 5bc - {2c}^{2} \\ = 3 {a}^{2} - 2 {b}^{2} - {2c}^{2} - ab + 5ac + 5bc$

Answer 2

Answer:

option a is correct

Step-by-step explanation:

(3a + 2b - c)(a - b + 2c)

3a(a- b + 2c) +2b(a - b + 2c) - c(a - b + 2c)

multiply the brackets

3a^2 - 3ab + 6ac + 2ab - 2b^2 + 4bc - ac + bc - 2c^2

combine like terms

3a^2 - ab + 5ac - 2b^2 + 5bc - 2c^2

3a^2 - 2b^2 - 2c^2 - ab + 5ac + 5bc