Question

right expansion of (2a-b+3c)²​

Answer 1

$by \: \: \: using \: \: \: the \: \: \: formula \: \: \\ \\ (a + b + c) ^{2} = {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ac) \\ \\ here \: a = 2a \\ b = - b \\ c = 3c \\ \\ \\ = ({2a})^{2} + ( { - b}^{2} ) + ({3c})^{2} + 2((2a \times - b) + ( - b \times 3c) + (2a \times 3c)) \\ \\ = 4 {a}^{2} + b + 9{c}^{2} + 2(( - 2ab) + ( - 3bc) + (6ac)) \\ \\ = 4 {a}^{2} + b + 9 {c}^{2} + 2( - 2ab - 3bc + 6ac) \\ \\ = 4 {a}^{2} + b + 9 {c}^{2} - 4ab - 6bc + 12ac \\ \\ \\ hope \: \: \: it \: \: \: helps$