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乘法公式的計算題４題急 )) 20點
(1) 99 × 101 + 26 × 24 - 992 - 252 = ＿＿＿＿＿ (2) 572 - 412÷572 + 82 × 57 + 412= (3) 512 - 102 × 89 + 892÷512 - 892 = (4) (299.5)2 + (199.5)2 - (100.5)2 - (200.5)2 = K 求Ｋ＝＿＿＿＿＿＿＿＿ 要用乘法公式 要有算式喔！感謝
最佳解答:
1. 99 × 101 + 26 × 24 - 992 - 252 =(100-1)(100+1)-(100-1)^2+(25-1)(25+1)-25^2 =(100-1)(100+1-100+1)+25^2-1^2-25^2 <------ a^2-b^2=(a+b)(a-b) =2*99-1 =197 2. 572 - 412÷572 + 82 × 57 + 412 =57^2+2*41*57+41^2-(41/57)^2 =(57+41)^2-(41/57)^2 =(98+41/57)(98-41/57) =9506 又 656/57^2 3. 512 - 102 × 89 + 892÷512 - 892 =51^2-2*51*89+89^2-2*89^2+(89/51)^2 =(51-89)^2-(2-1/51^2)*89^2 =38^2-5200*89^2/51^2 4. (299.5)2 + (199.5)2 - (100.5)2 - (200.5)2 =(300-0.5)^2+(200-0.5)^2-(100+0.5)^2-(200+0.5)^2 =300^2-300+0.5^2+200^2-200+0.5^2-100^2-100-0.5^2-200^2-200-0.5^2 =300^2-100^2-300-200-100-200 =80000-800 =79200
其他解答:CEE950A255C9C3B3
乘法公式的計算題４題急 )) 20點
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發問:(1) 99 × 101 + 26 × 24 - 992 - 252 = ＿＿＿＿＿ (2) 572 - 412÷572 + 82 × 57 + 412= (3) 512 - 102 × 89 + 892÷512 - 892 = (4) (299.5)2 + (199.5)2 - (100.5)2 - (200.5)2 = K 求Ｋ＝＿＿＿＿＿＿＿＿ 要用乘法公式 要有算式喔！感謝
最佳解答:
1. 99 × 101 + 26 × 24 - 992 - 252 =(100-1)(100+1)-(100-1)^2+(25-1)(25+1)-25^2 =(100-1)(100+1-100+1)+25^2-1^2-25^2 <------ a^2-b^2=(a+b)(a-b) =2*99-1 =197 2. 572 - 412÷572 + 82 × 57 + 412 =57^2+2*41*57+41^2-(41/57)^2 =(57+41)^2-(41/57)^2 =(98+41/57)(98-41/57) =9506 又 656/57^2 3. 512 - 102 × 89 + 892÷512 - 892 =51^2-2*51*89+89^2-2*89^2+(89/51)^2 =(51-89)^2-(2-1/51^2)*89^2 =38^2-5200*89^2/51^2 4. (299.5)2 + (199.5)2 - (100.5)2 - (200.5)2 =(300-0.5)^2+(200-0.5)^2-(100+0.5)^2-(200+0.5)^2 =300^2-300+0.5^2+200^2-200+0.5^2-100^2-100-0.5^2-200^2-200-0.5^2 =300^2-100^2-300-200-100-200 =80000-800 =79200
其他解答:CEE950A255C9C3B3
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