(1)已知2x=2,2y=4,求2x+y的值;(2)已知x2n=5,求(3x3n)2﹣4(x2)2n的值.
题型:解答题难度:一般来源:广西壮族自治区期末题
(1)已知2x=2,2y=4,求2x+y的值; (2)已知x2n=5,求(3x3n)2﹣4(x2)2n的值. |
答案
解:(1)∵2x=2,2y=4, ∴2x+y=2x ·2y=2×4=8; (2)(3x3n)2﹣4(x2)2n, =9(x2n)3﹣4(x2n)2, =9×53﹣4×52, =1025. |
举一反三
计算: (1)﹣3m(2m+n﹣1); (2)(3x﹣2)(x+4); (3)(x+y﹣2)(x+y+2). |
下列各式正确的是 |
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A.x5·x=x5 B.(2a3)2=4a6 C.a6÷a2=a3 D.a3+a2=2a5 |
计算: (1)(2xy2)2·(﹣3xy3); (2)(2x﹣3y)(x+2y)﹣(x+y)2 |
已知:2x=4y+1,27y=3x﹣1,求x﹣y的值 |
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