數學(展開)

1. (y-4)*2
= (y-4)(y-4)
= y(y-4) - 4(y-4)
= y*2 -4y - 4y + 16
= y*2 - 8y + 16

2. (2a + b)*2
= (2a + b) (2a + b)
= 2a(2a + b) + b(2a + b)
= 4a*2 + 2ab + 2ab + b*2
= 4a*2 + 4ab + b*2

1) (y-4)*2
=y*2-8x+16
2) (2a+b)*2
=4a*2+4ab+b*2