Question

simplify (3x+2y)^2+(3x-y)^2​

Answer 1

Answer:

$18x {}^{2} + 6xy + 5y {}^{2}$

Step-by-step explanation:

$\: \: (3x + 2y) {}^{2} + (3x - y) {}^{2} \\ \: (3x + 2y)(3x + 2y) + (3x - y)(3x - y) \\ \: 3x(3x + 2y) + 2y(3x + 2y) + 3x(3x - y) - y(3x - y) \\ \: 9x {}^{2} + 6xy + 6xy + 4y {}^{2} + (9x {}^{2} - 3xy - 3xy + y {}^{2} \\ \: 9x {}^{2} + 6xy + 6xy + 4y {}^{2} + 9x {}^{2} - 3xy - 3xy + y {}^{2} \\ \: 9x {}^{2} + 9x {}^{2} + 6xy + 6xy - 3xy - 3xy + 4y {}^{2} + y {}^{2} \\ \: \: = 18x {}^{2} + 6xy + 5y {}^{2}$