Question

Tìm x biết:
a) \(x:\left(-\dfrac{1}{2}\right)^3=-\dfrac{1}{2}\);                b) \(\left(\dfrac{3}{4}\right)^5.x=\left(\dfrac{3}{4}\right)^7\)

Answer 1

Lời giải:

a)

=> x =

b) =>

Answer 2

a) \(x:\left(-\dfrac{1}{2}\right)^3=-\dfrac{1}{2}\)

\(x=-\dfrac{1}{2}.\left(-\dfrac{1}{2}\right)^3\)

\(x=-\dfrac{1}{2}^{1+3}\)

\(x=-\dfrac{1}{2}^4\)

\(x=\dfrac{\left(-1\right)^4}{2^4}\)

\(x=\dfrac{1}{16}\)

b) \(\left(\dfrac{3}{4}\right)^5.x=\left(\dfrac{3}{4}\right)^7\)

\(x=\left(\dfrac{3}{4}\right)^7:\left(\dfrac{3}{4}\right)^5\)

\(x=\left(\dfrac{3}{4}\right)^{7-5}\)

\(x=\left(\dfrac{3}{4}\right)^2\)

\(x=\dfrac{3^2}{4^2}\)

\(x=\dfrac{9}{16}\)

Answer 3

a,\(x\div\left(-\dfrac{1}{8}\right)=-\dfrac{1}{2}\)

\(x=-\dfrac{1}{2}\cdot\left(-\dfrac{1}{8}\right)\)

\(x=\dfrac{1}{16}=\left(\dfrac{1}{2}\right)^4\)

Answer 4

b,\(\left(\dfrac{3}{4}\right)^5\cdot x=\left(\dfrac{3}{4}\right)^7\)

\(x=\left(\dfrac{3}{4}\right)^7\div\left(\dfrac{3}{4}\right)^5\)

\(x=\left(\dfrac{3}{4}\right)^{7-5}\)

\(x=\left(\dfrac{3}{4}\right)^2\)

\(x=\dfrac{9}{16}\)

Answer 5

Bài 30 Tìm x, biết

a)

b)

Lời giải:

a) => x =

b) =>

Answer 6

Answer 7

\(a,\) \(x:\left(-\dfrac{1}{2}\right)^3=-\dfrac{1}{2}\\ \Rightarrow x=-\dfrac{1}{2}.\left(-\dfrac{1}{2}\right)^3\\ \Rightarrow x=-\dfrac{1}{3}^4\\ \Rightarrow x=\dfrac{1}{81}\)

b,

\(\left(\dfrac{3}{4}\right)^5.x=\left(\dfrac{3}{4}\right)^7\\ \Rightarrow x=\left(\dfrac{3}{4}\right)^7:\left(\dfrac{3}{4}\right)^5\\\Rightarrow x=\left(\dfrac{3}{4}\right)^2\\ \Rightarrow x=\dfrac{9}{16}\)

Answer 8

a) x:(\(\dfrac{-1}{2}\) )³=-\(\dfrac{-1}{2}\)

x= \(\dfrac{-1}{2}\) . \(\left(\dfrac{-1}{2}\right)\)³

x= \(\dfrac{-1}{2}\) . \(\left(\dfrac{-1}{8}\right)\)

x= \(\dfrac{1}{16}\)

B) \(\left(\dfrac{3}{4}\right)\)⁵ .x =\(\left(\dfrac{3}{4}\right)\)⁷

x=\(\left(\dfrac{3}{4}\right)\)⁷ : \(\left(\dfrac{3}{4}\right)\)⁵

x=\(\left(\dfrac{3}{4}\right)\)²

x=\(\dfrac{9}{16}\)