Question

[nguyen thi anh suong]

Tìm x biết

a) 2/3+ 7/4 : x = 5/6

b) (x + 5/3) . (x - 5/4)= 0

c) (x- 1,2)^2 = 4

d) (x +1)^3 = -125

Answer 1

[Diệu Huyền]

\(a,\frac{2}{3}+\frac{7}{4}:x=\frac{5}{6}\)

\(\Leftrightarrow\frac{7}{4}:x=\frac{5}{6}-\frac{2}{3}\)

\(\Leftrightarrow\frac{7}{4}:x=\frac{1}{6}\)

\(\Leftrightarrow x=\frac{21}{2}\)

\(b,\left(x+\frac{5}{3}\right).\left(x-\frac{5}{4}\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\frac{5}{3}=0\\x-\frac{5}{4}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\frac{5}{3}\\\frac{5}{4}\end{matrix}\right.\)

\(c,\left(x-1,2\right)^2=4\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1,2=2\\x-1,2=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3,2\\x=-0,8\end{matrix}\right.\)

\(d,\left(x+1\right)^3=-125\)

\(\Leftrightarrow\left(x+1\right)^3=\left(-5\right)^3\)

\(\Leftrightarrow x+1=-5\)

\(\Leftrightarrow x=-6\)

Vậy ...........................................................

Answer 2

[nguyen thi anh suong]

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