Bài 1: Tìm n \(\in\) Z biết:
\(e)3^{-1}.3^n+6.3^{n-1}=7.3^6\)
\(g)3^4< \dfrac{1}{9}.27^n< 3^{10}\)
\(h)25< 5^n:5< 625\)
Bài 2: Tìm x biết:
\(\dfrac{2.\left(\dfrac{-1}{2}\right).\left(\dfrac{2}{3}\right)^2-3.\left(\dfrac{-1}{2}\right)^2.\dfrac{2}{3}+1}{3.\left(\dfrac{-1}{2}\right)-\dfrac{2}{3}}\)
Help me !!!!!!!!!!!!! giúp mk vs các bn giỏi toán
\(\dfrac{\left(\dfrac{-5}{7}\right)^n}{\left(\dfrac{-5}{7}\right)^{n-1}}\left(n\ge1\right)\) Tính
b) \(\dfrac{\left(-\dfrac{1}{2}\right)^{2n}}{\left(-\dfrac{1}{2}\right)^n}\left(n\in N\right)\)
1,Tìm x,biết
a,\(\left(-1\dfrac{3}{5}+x\right)\div\dfrac{12}{13}=2\dfrac{1}{6}\)
b,\(\dfrac{-4}{7}x+\dfrac{7}{5}=\dfrac{1}{8}\div\left(-1\dfrac{2}{3}\right)\)
Viết các biểu thức số sau dưới dạng \(a^n,\left(a\in\mathbb{Q},n\in\mathbb{N}\right)\) :
a) \(9.3^3.\dfrac{1}{81}.3^2\)
b) \(4.2^5:\left(2^3.\dfrac{1}{16}\right)\)
c) \(3^2.2^5.\left(\dfrac{2}{3}\right)^2\)
d) \(\left(\dfrac{1}{3}\right)^2.\dfrac{1}{3}.9^2\)
Mấy chế zô giải giùm tui câu này:
Cho \(A=\left(\dfrac{1}{2^2}-1\right)\left(\dfrac{1}{3^2}-1\right)\left(\dfrac{1}{4^2}-1\right).....\left(\dfrac{1}{2013^2}-1\right)\left(\dfrac{1}{2014^2}-1\right)\) và \(B=-\dfrac{1}{2}.\)
Hãy so sánh A và B.
2) tìm số tự nhiên n biết:
\(\left(\dfrac{1}{3}\right)^n=\dfrac{1}{27};\left(\dfrac{3}{5}\right)^n=\dfrac{81}{625}\)
a) \(x:\left(-\dfrac{1}{2}\right)^3=-\dfrac{1}{2}\)
b)\(\left(\dfrac{3}{4}\right)^2.x=\left(\dfrac{3}{4}\right)^5\)
Tìm x biết :
a) \(x^2-3=1\)
b) \(2x^3+12=-4\)
c) \(\left(2x-3\right)^2=16\)
d) \(x:\left(\dfrac{-1}{2}\right)^1=\dfrac{-1}{2}\)
h) \(\left(\dfrac{1}{4}-x\right)^2=\dfrac{25}{16}\)
i) \(\left(x+\dfrac{1}{3}\right)^3=\dfrac{-1}{8}\)
k) \(\left(\dfrac{1}{2}-x\right)^2=1\)
bài 1 tính
a/ \(\left|1\dfrac{1}{2}-2\dfrac{1}{3}\right|^2+\left|1-\dfrac{5}{4}\right|\)
b/\(\left|\left(-1\right)^{100}-2\dfrac{1}{3}\right|+\dfrac{5}{6}\)
c/\(\left|\left(\dfrac{2}{3}\right)^{-1}-\dfrac{7}{4}\right|-\dfrac{7}{4}\)
d/ \(\left|x-5\right|+\left|x-8\right|\) với 5 \< x>/