Question

Class 8 students or elderly, please help me with this question...!!!​

Answer 1

$- 7ac - 5ab + 2bc - 3a {}^{2} + 2b { }^{2} + 4c {}^{2}$

Answer 2

Step-by-step explanation:

3a(a+b+c) = 3a^2 + 3ab + 3ac

2b(a-b+c) = 2ab - 2b^2 + 2bc

4c(-a+b+c) = -4ac + 4bc + 4c^2

3a(a+b+c) - 2b(a-b+c)  = 3a^2 + 3ab + 3ac -  [2ab - 2b^2 + 2bc ]

                                    = 3a^2 + 3ab + 3ac -  2ab + 2b^2 - 2bc

                                     = 3a^2 + 2ab + 2b^2 - 3ac - 2bc

4c(-a+b+c) - [3a(a+b+c) - 2b(a-b+c) ]

= -4ac + 4bc + 4c^2 - [3a^2 + 2ab + 2b^2 - 3ac - 2bc]

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

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