(x+2)^4
=[(x+2)²]²
=(x²+4x+4)²
=x²(x²+4x+4)+4x(x²+4x+4)+4(x²+4x+4)
=x的4次方+4x³+4x²+4x³+16x²+16x+4x²+16x+16
=x的4次方+8x³+24x²+32x+16
(x+2)^4
=[(x+2)²]²
=(x²+4x+4)²
=x²(x²+4x+4)+4x(x²+4x+4)+4(x²+4x+4)
=x的4次方+4x³+4x²+4x³+16x²+16x+4x²+16x+16
=x的4次方+8x³+24x²+32x+16