Question

4. Find the product of ( a-b+3c) and ( a + 2b )​

Answer 1

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

${a}^{2} - ab + 3ac + 2ab - {2b}^{2} + 6ac$

${a}^{2} + ab + 9ac - {2b}^{2}$