解析 A [解析] 因为x和y都是整数,所以由x2<y可以推出一定有x<y,从而充分地回答了x不大于y,所以(1)充分(注:对题目中的问题否定的回答也是充分的回答);通过举例可以验证(2)不充分,如对于满足[*]的x=1,y=2有x<y,而对于满足[*]的x=4,y=3,则有x>y。
且x是y的倍数的y有无穷多个,此时y既可以等于2,也可以不等于2;根据(2)可设x+2=ny,由x是y的倍数可设x=my,其中m和n都是正整数,把这两个式子相减可得(n-m)y=2,因为n-m和y都是正整数,所以当n-m取1时,y取2,当n-m取2时,y取1,因此(2)也不充分;根据以上分析可知(1)+(2)时,y=2,所以(1...
2 If x and y are positive integers such that x=8y+12,what is the greatest common divisor of x and 1) x=12u,where u is an integer 2) y=12z,where z is 由题知:x=4(2y+3) 由(1)知:x=12u 则y=3k k is an integer.x=12(2k+1) 则x,y最大公因子不能确定. 由(2)知:y=12...
If x and y are positive integers such that 3x+7y=88. Find the maximum value of x+y. 已知x、y为正整数且3x+7y=88,求x+y的最大值. 相关知识点: 试题来源: 解析 28. 已知x,y为正整数且3x+7y=88, 所以1⩽y⩽12,且3x与7y同为奇数或同为偶数, 当3x,7y均为奇数时,则x,y均为...
If x and y are positive integers such that the greatest common factor of x^2y^2 and xy^3 is 27, then which of the following could y equal? ( ) A. 81 B. 27 C. 18 D. 9 E. 3 相关知识点: 试题来源: 解析 E The correct answer is E. You could take a "bruteforce" approach ...
If x and y are positive integers such that the greatest common factor of and is 27, then which of the following could y equal? ( )A. 81B. 27C. 18D. 9E. 3 答案 E相关推荐 1If x and y are positive integers such that the greatest common factor of and is 27, then which of the...
百度试题 结果1 题目If x and y are positive integers and 3^(2x)⋅3^(2y)=81, what is the value of x+y? () A. 32 B. 2 C. 4 D. (81)2 E. 81 相关知识点: 试题来源: 解析 B 反馈 收藏
5.If x and y are positive integers for which 23=1296,what is the value of x+y?((A)8(B)9(C)10(D)115.If x and y are positive integers for which 2r3 y=1296, what is the value of x+y?( ) (A)8 (B)9 (C)10 (D)11 答案 5.A优质解答相关...
If x and y are positive integers such that x = 8y + 12, what is the greatest common divisor of x and y ? (1)x = 12u, where u is an integer. (2)y = 12z, where z is an integer. 选项: A、Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient....
If x and y are positive integers such that x = 8y + 12, what is the greatest common divisor of x and y ? (1)x = 12u, where u is an integer. (2)y = 12z, where z is an integer.A、Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient. B、...