標題:
中三-把多項式分解為因式~高手入!!15點!
發問:
把多項式分解為因式 1) g2 + 10g _25 2) 16a2 +8a + 1 3) 9s2 - 6s + 1 4) 36-12a + a2 5) 25p2 +60pq +36q2 把下列各式分解為因式 6) 8- 40L +50L2 7) 80R2 + 40RS +5S2 吾該曬高人!! 要埋步驟! thx!
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最佳解答:
1) g2+10g+25 =g2+2(5g)+52 =(g+5)2 2) 16a2+8a+1 =(4a)2+2(4a)(1)+12 =(4a+1)2 3) 9s2-6s+1 =(3s)2-2(3s)(1)+12 =(3s-1)2 4) 36-12a+a2 =a2-12a+36 =a2-12a+62 =a2-2(6a)+62 =(a-6)2 5) 25p2+60pq+36q2 =(5p)2+2(5p)(6q)+(6q)2 =(5p+6q)2 6) 8-40L+50L2 =50L2-40L+8 =2(25L2-20L+4) =2[(5L)2-2(5L)(2)+22] =2(5L-2)2 7) 80R2+40RS+5S2 =5(16R2+8RS+S2) =5[(4R)2+2(4R)(S)+S2] =5(4R+S)2
其他解答:
1) g2 + 10g+25 =(g+5)^2 2) 16a2 +8a + 1 =(4a+1)^2 3) 9s2 - 6s + 1 =(3s-1)^2 4) 36-12a + a2 =(a-6)^2 5) 25p2 +60pq +36q2 =(5p+6q)^2 6) 8- 40L +50L2 =2(4-20L+25L^2) =2(5L-2)^2 7) 80R2 + 40RS +5S2 =5(16R^2+8RS+S^2) =5(4R+S)^2|||||中六學生咁既錯都可以犯？ 笑死人咩|||||To : LeeSin ying 第6題及第7題出現了一個嚴重錯誤 !!! 6. 8- 40L +50L2 不等於 25L^2 - 20L + 4 應該是 8- 40L +50L2 = 2(25L^2 - 20L + 4) =2[(5L)^2 - 2(5L)(2) + (2)^2] =2(5L - 2)^2 7. 如上題同一道理|||||1) g2 + 10g +25 =g2 +2(5)g+52 =(g+5)2 2) 16a2 +8a + 1 =(4a)2+2(1)(4a)+12 =(4a+1)2 3) 9s2 - 6s + 1 =(3s)2 - 2(1)(3s) + 12 =(3s-1)2 4) 36-12a + a2 =a2 - 2(6)a+62 =(a-6)2 5) 25p2 +60pq +36q2 =(5p)2+2(5p)(6q)+(6q)2 =(5p+6q)2 6) 8- 40L +50L2 =25L2 - 20L+4 =(5L)2 - 2(2)(5L)+22 =(5L-2)2 7) 80R2 + 40RS +5S2 =16R2+8RS+S2 =(4R)2+2(4R)S+S2 =(4R+S)2
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