Question

Efectuati:
a) -3pe4 + 5pe6
b) 5pe8 - 2
c) -3pe10 × (-15pe9)
d) 28pe12 - 35pe15
e) 2pe3 ÷ (-12)
f) -5pe3 + 1

Answer 1

Răspuns:

Explicație pas cu pas:

a) numitorul comun 12

$\frac{-3}{4} + \frac{5}{6} = \frac{-9+10}{12}=\frac{1}{12}$

b)

numitorul comun 8

$\frac{5}{8} -2=\frac{5-16}{8} = \frac{-11}{8}$

c)

$\frac{-3}{10} * \frac{-15}{9}= \frac{45}{90} = \frac{1}{2}$

simplificam ( impartim cu 45 sus si jos )

d)

$\frac{28}{12} -\frac{35}{15} = \frac{28*15-35*12}{12*15} =\frac{420-420}{180} = \frac{0}{180} = 0$

e)

$\frac{2}{3} : ( - 12 ) =\frac{2}{3} * \frac{1}{-12} = \frac{2}{-36} = \frac{1}{-18 } = - \frac{1}{18}$

f)$\frac{-5}{3}+1=\frac{-5+3}{3}=\frac{-2}{3}=-\frac{2}{3}$

Answer 2

    a) $-\frac{3}{4} + \frac{5}{6} =$

    $-\frac{3*3}{3*4} + \frac{2*5}{2*6}=$

    $-\frac{9}{12} + \frac{10}{12} = \frac{1}{12}$

    b) $\frac{5}{8} - 2 =$

    $\frac{5}{8} - \frac{2}{1} =$

    $\frac{5}{8} - \frac{2*8}{1*8} =$

    $\frac{5}{8} - \frac{16}{8} = -\frac{11}{8}$

   

    c) $-\frac{3}{10} * (-\frac{15}{9}) =$

    $\frac{45}{90} = \frac{9}{18} = \frac{1}{2}$

    d) $\frac{28}{12} - \frac{35}{15}$

    $\frac{28*15}{12*15} - \frac{35*12}{12*15} =$

    $\frac{420}{180} - \frac{420}{180} =$

    $\frac{0}{180} = 0$

    e) $\frac{2}{3} : (-12) =$

    $\frac{2}{3} : (-\frac{12}{1}) =$

    $\frac{2}{3} * (-\frac{1}{12}) =$

    $-\frac{2}{36} = -\frac{1}{18}$

    f) $-\frac{5}{3} + 1 =$

    $-\frac{5}{3} + \frac{1}{1} =$

    $-\frac{5}{3} + \frac{1*3}{1*3} =$

    $-\frac{5}{3} + \frac{3}{3} = -\frac{2}{3}$