功課 help math................................................

1. 4-y= 4-(-2)=4+2=6 (負負得正, - (-2) = +2)

2. (4y)2= 4y*4y= 4*(-2) * 4*(-2) = -8 * -8 =+16 (負負得正)

3. (8+Y)2 = (8+y) * (8+y) = (8 + (-2)) * (8+ (-2)) = (8-2) *(8-2) = 6 * 6 = 36 (正負得負, 8+ (-2) = 8-2=6)

注: 二次方打唔到出黎, 正確寫法應為 ( ) 外右上方

1. 4-y=4-(-2)
=4+2
=6

2. 4y二次方=4(-2)二次方
=4(4)
=16

3. 8+y二次方=8+(-2)二次方
=8+4
=12

1. (4-y)2
=(4-y)(4-y)
=16-8y+y2

2. (4y) 2
=16y2

3 (4+y) 2
=(4+y)(4+y)
=16+8y+y2

假設y= 負2
1. 4-y=6 [4-(-2)]
2. 4y二次方=-16 (4 y二次方,,只係個-2有份,,四冇二次方)
3. 8+y二次方=8+(-2)二次方=8+2=10

2007-10-11 10:26:46 補充：
樓上個個,,no.2 = -16呀

2007-10-11 10:27:38 補充：
仲有我個題係3. 8 y二次方=8 (-2)二次方=8 2=12唔係10,,打錯

1. +6
2. +16
3. +12