计算这些题①(2a-b+3c)²②(a+1/3)²(a-1/3)²③(m-n)(m²-n²)(m-n)④

问题描述:

计算这些题①(2a-b+3c)²②(a+1/3)²(a-1/3)²③(m-n)(m²-n²)(m-n)④
①(2a-b+3c)²②(a+1/3)²(a-1/3)²③(m-n)(m²-n²)(m-n)④(2a+b)²-2(2a+b)(a-2b)+(a-2b)²

1⃣️4a2+b2+9c2+12ac-4ab-6bc2⃣️a2-1/93⃣️m4-n4-2m3n+2mn34⃣️a2+9b2+6ab