Question

Tìm x , biết : 

a) -\(\frac{2}{3}\) : x + \(\frac{5}{8}\) = -\(\frac{7}{12}\)

b) ( 2x + 3 )² = 25 

Ghi cách làm , cả đáp án nha !

Answer 1

a) \(\frac{-2}{3}\) : x + \(\frac{5}{8}\) = \(\frac{-7}{12}\)

\(\frac{-2}{3}\) : x = \(\frac{-7}{12}-\frac{5}{8}\)

\(\frac{-2}{3}:x=\frac{-14}{24}-\frac{15}{24}\)

\(\frac{-2}{3}:x=\frac{-29}{24}\)

\(x=\frac{-2}{3}:\frac{-29}{24}\)

\(x=\frac{-2}{3}.\frac{-24}{29}\)

\(x=\frac{-2.\left(-8\right)}{1.29}\)

Vậy \(x=\frac{16}{29}\)

b) (2x + 3)²  = 25

(2x +3)² = 5²

\(\Rightarrow\) 2x + 3 = 5

           2x = 5 -3

           2x = 2

           x = 2 : 2

            x = 1

          Vậy x =1