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發問:
1)the sum of two numbers is 9 times their difference,and the difference of their square os 81.find the numbers.2)a two-digit number is less than three times the product of its digit by 8,and the digit in the tenth place exceeds the digit in the unit place by 2.find the number.3)the perimeter of a... 顯示更多 1)the sum of two numbers is 9 times their difference,and the difference of their square os 81.find the numbers. 2)a two-digit number is less than three times the product of its digit by 8,and the digit in the tenth place exceeds the digit in the unit place by 2.find the number. 3)the perimeter of a rectangular playground is 324m.the length is increased by 6m and the width by 3m.the area is then increased by 1/9 of its former value.find the original dimensions of the playground.
最佳解答:
1 let a and b be the numbers required where a>b a+b = 9 ( a-b) a=5b/4 and a2-b2 = 81 (5b/4)2 - b2 =81 b=12 a=15 2 let (10a+b) be the number (10a+b) + 8 = 3ab and a=2+b so b=4 or b=-7/3 (rejected) a=6 3 let a be the length and b be the width 2(a+b) = 324 (a+6)(b+3) = ab(1+1/9) by solving the equations, a=72m b= 63m
其他解答:63D0B758E2D502CC
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polynomial&equation的文字題發問:
1)the sum of two numbers is 9 times their difference,and the difference of their square os 81.find the numbers.2)a two-digit number is less than three times the product of its digit by 8,and the digit in the tenth place exceeds the digit in the unit place by 2.find the number.3)the perimeter of a... 顯示更多 1)the sum of two numbers is 9 times their difference,and the difference of their square os 81.find the numbers. 2)a two-digit number is less than three times the product of its digit by 8,and the digit in the tenth place exceeds the digit in the unit place by 2.find the number. 3)the perimeter of a rectangular playground is 324m.the length is increased by 6m and the width by 3m.the area is then increased by 1/9 of its former value.find the original dimensions of the playground.
最佳解答:
1 let a and b be the numbers required where a>b a+b = 9 ( a-b) a=5b/4 and a2-b2 = 81 (5b/4)2 - b2 =81 b=12 a=15 2 let (10a+b) be the number (10a+b) + 8 = 3ab and a=2+b so b=4 or b=-7/3 (rejected) a=6 3 let a be the length and b be the width 2(a+b) = 324 (a+6)(b+3) = ab(1+1/9) by solving the equations, a=72m b= 63m
其他解答:63D0B758E2D502CC
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