Question

3A + 4 b + 5 C whole square

Answer 1

${(3a + 4b + 5c)}^{2}$
=
${9a}^{2} + {16b }^{2} + {25c}^{2} + 2(3)(4)ab + 2(4)(5)bc + 2(5)(3)ca$
=
$9 {a }^{2} + 16 {b}^{2} + 25 {c}^{2} + 24ab + 40bc + 30ca$

Answer 2

(3a + 4b + 5c)²


We will use the formula of (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ac


=> (3a)² + (4b)² + (5c)² + 2 × 3a × 4b + 2 × 4b × 5c + 2 × 3a × 5c

=> 9a² + 16b² + 25c² + 24ab + 40bc + 30ac


$\therefore{}$ (3a + 4b + 5c)² = 9a² + 16b² + 25c² + 24ab + 40bc + 30ac