Mr.Phong is Mai's father

1. B

2. B

3. A

 chúc bn làm tốt =)))

78,56 x 2,25 = 176,76

3 tỉnh ko có chữ a là:

1. Điện Biên

2. Phú Thọ

3. Hưng Yên

bắt quả tang nhá

 a,   \(\dfrac{3}{8}\) - \(\dfrac{1}{6}\)x = \(\dfrac{1}{4}\)

            \(\dfrac{1}{6}\) x = \(\dfrac{1}{8}\)

                x = \(\dfrac{1}{8}\) : \(\dfrac{1}{6}\)

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

  b,    \(^{\text{(x−1) }^2}\) = \(\dfrac{1}{4}\)

    a,     \(\dfrac{1}{3}\) + \(\dfrac{3}{4}\) - \(\dfrac{5}{6}\)

       =   \(\dfrac{13}{12}\) - \(\dfrac{5}{6}\)

       =   \(\dfrac{1}{4}\)

    b,      \(\dfrac{-2}{3}\) + \(\dfrac{6}{5}\) : \(\dfrac{2}{3}\) - \(\dfrac{2}{15}\)

       =    ( \(\dfrac{-2}{3}\) + \(\dfrac{2}{3}\) ) : ( \(\dfrac{6}{5}\) - \(\dfrac{2}{15}\) )

       =                 \(\dfrac{1}{3}\)  :  \(\dfrac{16}{15}\)

       =                    \(\dfrac{5}{16}\)

    c,      \(\dfrac{-3}{7}\) +\(\dfrac{5}{13}\) + \(\dfrac{-4}{7}\)

       =     ( \(\dfrac{-3}{7}\) + \(\dfrac{-4}{7}\) ) + \(\dfrac{5}{13}\)

       =              1 + \(\dfrac{5}{13}\)

       =                \(\dfrac{18}{13}\) = 1\(\dfrac{5}{13}\)

    d,       \(\dfrac{12}{19}\) + \(\dfrac{-8}{13}\) - \(\dfrac{12}{19}\) + \(\dfrac{5}{-13}\) + 2

       =      2 . \(\dfrac{12}{19}\) - ( \(\dfrac{-8}{13}\) + \(\dfrac{5}{-13}\) + 2 )

       =          \(\dfrac{24}{19}\) - 1

       =             \(\dfrac{5}{\text{​​}19}\)