12xy一2x的平方一18y的平方
=-2(x²-6xy+9y²)
=-2(x-3y)²
-3x²+48
=-3(x²-16)
=-3(x+4)(x-4)
6m(m一3)一8(3一m)
=6m(m-3)+8(m-3)
=2(m-3)(3m+4)
2a^4-8
=2(a^4-4)
=2(a²+2)(a²-2)
=2(a²+2)(a+√2)(a-√2)
12xy一2x的平方一18y的平方
=-2(x²-6xy+9y²)
=-2(x-3y)²
-3x²+48
=-3(x²-16)
=-3(x+4)(x-4)
6m(m一3)一8(3一m)
=6m(m-3)+8(m-3)
=2(m-3)(3m+4)
2a^4-8
=2(a^4-4)
=2(a²+2)(a²-2)
=2(a²+2)(a+√2)(a-√2)