Explicação passo-a-passo:
A)
[tex] \dfrac{9}{10} + \dfrac{3}{2} - \dfrac{2}{5} + 2[/tex]
[tex] \dfrac{9 + 15 - 4 + 20}{10} [/tex]
[tex] \dfrac{40}{10} [/tex]
[tex]4[/tex]
B)
[tex] \dfrac{2}{12} + \dfrac{7}{8} + \dfrac{1}{4} [/tex]
[tex] \dfrac{2 {}^{ \div 2} }{12 {}^{ \div 2} } + \dfrac{7}{8} + \dfrac{1}{4} [/tex]
[tex] \dfrac{1}{6} + \dfrac{7}{8} + \dfrac{1}{4} [/tex]
[tex] \dfrac{4 + 21 + 6}{24} [/tex]
[tex] \dfrac{31}{24} [/tex]
A+B
[tex]4 + \dfrac{31}{24} [/tex]
[tex] \dfrac{96 + 31}{24} [/tex]
[tex] \dfrac{127}{24} [/tex] >>> resposta
A)
[tex] \dfrac{4}{5} - \dfrac{1}{10} - \dfrac{2}{5} [/tex]
[tex] \dfrac{4 - 2}{5} - \dfrac{1}{10} [/tex]
[tex] \dfrac{2}{5} - \dfrac{1}{10} [/tex]
[tex] \dfrac{4 - 1}{10} [/tex]
[tex] \dfrac{3}{10} [/tex]
B)
[tex] \dfrac{2}{3} - \dfrac{1}{4} [/tex]
[tex] \dfrac{8 - 3}{12} [/tex]
[tex] \dfrac{5}{12} [/tex]
A+B
[tex] \dfrac{3}{10} + \dfrac{5}{12} [/tex]
[tex] \dfrac{18 + 25}{60} [/tex]
[tex] \dfrac{43}{60} [/tex] >>> resposta
A)
[tex]3 - \dfrac{1}{2} [/tex]
[tex] \dfrac{6 - 1}{2} [/tex]
[tex] \dfrac{5}{2} [/tex]
B)
[tex]a - \dfrac{3}{4} [/tex]
A+B
[tex] \dfrac{5}{2} + a - \dfrac{3}{4} [/tex]
[tex] \dfrac{5}{2} - \dfrac{3}{4} + a[/tex]
[tex] \dfrac{10 - 3}{4} + a[/tex]
[tex] \dfrac{7}{4} + a[/tex]>>> resposta
