Question

(3a-7b-c)² का प्रसार कीजिए ​

Answer 1

$(3a - 7b - c)^{2} = \\ 9 {a}^{2} + 49 {b}^{2} + {c}^{2} - 42ab + 14bc -6ac$

we know that (a+b+c)^2= a^2+ b^2+c^2+2ab+2bc+2ca.