Question

tính hợp lí: -7/9 . 4/11 + -7/9 . 7/11 + 5 7/9

giúp vs mn ơi

Answer 1

\(\frac{-7}{9}\cdot\frac{4}{11}+\frac{-7}{9}\cdot\frac{7}{11}+5\frac{7}{9}\)

\(=\frac{-7}{9}\cdot\left[\frac{4}{11}+\frac{7}{11}\right]+5\frac{7}{9}\)

\(=\frac{-7}{9}\cdot1+5+\frac{7}{9}\)

\(=\frac{-7}{9}+5+\frac{7}{9}=\frac{-7}{9}+\frac{7}{9}+5=5\)

Answer 2

\(\frac{-7}{9}.\frac{4}{11}+\frac{-7}{9}+\frac{7}{11}+5\frac{7}{9}\)

\(=\frac{-7}{9}.\left(\frac{4}{11}+\frac{7}{11}\right)+\frac{52}{9}\)

\(=\frac{-7}{9}.1+\frac{52}{9}\)

\(=\frac{-7}{9}+\frac{52}{9}\)

\(=\frac{45}{9}=5\)

Answer 3

-7/9 . 4/11 + (-7/9) . 7/11+ 5 . 7/9= -7/9 .( 4/11+ 7/11)+(-5) .(- 7/9)

                                               = -7/9 . 1 +(-5) . (-7/9)

                                               = -7/9.(1 + -5)

                                               = -7/9 . (-4)

                                               =28/4