问题
解答题
已知9n+32n-1=8,求(33n)2-6×92n的值.
答案
∵9n+32n-1=8,
∴32n+32n•
=8,1 3
∴32n(1+
)=8,1 3
∴32n=6,
∴(33n)2-6×92n=(32n)3-6×(32n)2=63-6×62=0.
已知9n+32n-1=8,求(33n)2-6×92n的值.
∵9n+32n-1=8,
∴32n+32n•
=8,1 3
∴32n(1+
)=8,1 3
∴32n=6,
∴(33n)2-6×92n=(32n)3-6×(32n)2=63-6×62=0.