Question

Thuc hien phep tinh :

a) 4 phan 5 + -7 phan 15 . 1, 25

b)  2 phan 5 + 3 phan 5 .  ( 4 1phan2 - 3,25)

Answer 1

a) 13/60

b)43/4

Answer 2

 \(\frac{4}{5}+\frac{-7}{15}.1,25\)

\(=\frac{4}{5}+\frac{-7}{12}\)

\(=\frac{13}{60}\)

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Answer 3

a)  \(\frac{4}{5}\)+\(\frac{-7}{15}\) x  \(1,25\)

= \(\frac{4}{5}\)+ \(\frac{-7}{15}\)x   \(\frac{5}{4}\)

= \(\frac{4}{5}\)+\(\frac{-7}{12}\)

= \(\frac{48}{60}\)+ \(\frac{-35}{60}\)

=  \(\frac{13}{60}\)

b \(\frac{2}{5}\)+ \(\frac{3}{5}\)x  \(\left(4\frac{1}{2}-3,25\right)\)

= \(\frac{2}{5}\)+\(\frac{3}{5}\)x \(\left(\frac{9}{2}-\frac{13}{4}\right)\)

=\(\frac{2}{5}\)+\(\frac{3}{5}\)x\(\frac{5}{4}\)

=\(\frac{2}{5}\)+\(\frac{3}{4}\)

= \(\frac{8}{20}\)+\(\frac{15}{20}\)

=\(\frac{23}{20}\)