部落格

標題:

F.2Maths!!!!!!!!!!!40p!!!!!!

• 請問朗屏點去伊利沙伯體育館-
• 可以MSN名的符號..-v-
• 我想知邊度有酒樓會營業至零晨時份-

此文章來自奇摩知識+如有不便請留言告知

發問:

9. Factorize the following expressions.(a) (3a + b)2− (6a − b)2 (b) (x − 2y)2− (2x − 2y)2(c) (10x + 3y)2− (3x − 10y)2 (d) (x2− 6xy + 9y2) − x410. Factorize the following expressions.(a) (3a − b)2+ 10(3a − b) + 25 (b) 64(2x +... 顯示更多 9. Factorize the following expressions. (a) (3a + b)2 ? (6a ? b)2 (b) (x ? 2y)2 ? (2x ? 2y)2 (c) (10x + 3y)2 ? (3x ? 10y)2 (d) (x2 ? 6xy + 9y2) ? x4 10. Factorize the following expressions. (a) (3a ? b)2 + 10(3a ? b) + 25 (b) 64(2x + y)2 ? 80(2x + y) + 25 (c) 81(2x ? 3y)2 + 36(2x ? 3y) + 4 (d) 72(5x + 3y)2 ? 120(5x + 3y) + 50 11. Factorize the following expressions. (a) (x2 + 2x + 1) + xy + y (b) 9a2b2 ? (a2b2 ? 10ab3 + 25b4) 12. Find the values of the following by using identities. (a) 301^2 (b) 199^2 (c) 234^2 ? 2332 (d) 318^2 ? 282^2

最佳解答:

9. (a) (3a + b)2 ? (6a ? b)2 = 2(3a+b-6a+b) =2(2b-3a)// (b) (x ? 2y)2 ? (2x ? 2y)2 = 2(x-2y-2x+2y) = 2(-x) =-2x// (c) (10x + 3y)2 ? (3x ? 10y)2 = 2(10x+3y-3x+10y) =2(7x+13y)// (d) (x2? 6xy + 9y2) ? x4 9y2??????? 應該打錯～

其他解答:

9a) (3a + b)^2? (6a ? b)^2 =[3a + b)? (6a ? b) ][(3a + b)+6a ? b)] =(2b-3a)(9a) 9b) (x ? 2y)^2 ? (2x ? 2y)^2 =[(x ? 2y)-(2x ? 2y)][(x ? 2y)+(2x ? 2y)] =(-x)(3x-4y) 9c) (10x + 3y)^2? (3x ? 10y)^2 =[(10x + 3y)-(3x ? 10y)][(10x + 3y)+(3x ? 10y)] =(7x+13y)(13x-7y) 9d) (x2? 6xy + 9y2) ? x4 =(x-3)2? x4 =(-x2+x-3)(x2+x-3) 10a) (3a ? b)2 + 10(3a ? b) + 25 =[(3a-b)+5]2 10b) 64(2x + y)2 ? 80(2x + y) + 25 =[8(2x+y)+5]2 =(16x+8y+5)2 10c) 81(2x ? 3y)2 + 36(2x ? 3y) + 4 =[9(2x-3y)+2]2 =(18x-27y+2)2 10d) 72(5x + 3y)2 ? 120(5x + 3y) + 50 =0.5[144(5x + 3y)2 ? 240(5x + 3y) + 100] =0.5[12(5x+3y)-10]2 =0.5(60x+36y-10)2 11a) (x2 + 2x + 1) + xy + y =(x+1)2+y(x+1) =(x+1)(x+y+1) 11b) 9a2b2 ? (a2b2 ? 10ab3 + 25b4) =[9a2 ? (a2 ? 10ab + 25b2)]b2 =[(3a)2 ? (a ? 5b)]b2 =[(3a-a+5b)(3a+a-5b)]b2 =(2a+5b)(4a-5b)(b2) 12a) 301^2=(300+1)^2=90000+600+1=90601 12b) 199^2=(200-1)^2=40000-400+1=39601 12c) 234^2-2332 =.? 12d) 318^2-282^2 =(318-282)(318+282) =36*600 =21600 2009-10-03 14:54:35 補充： if... 12c) 234^2-233^2 打錯字自己計啦... =_="A9A3995907B431A4