Question

a expressao abaixo é igual ao numero racional a/b, e a e b nao tem fatores comuns. encontre a + b

Answer 1

$\large\boxed{\begin{array}{l}\rm\dfrac{\dfrac{2}{3}-\dfrac{5}{18}}{\dfrac{10}{24}+\dfrac{20}{36}}\\\\\rm\dfrac{\dfrac{12-5}{18}}{\dfrac{30+40}{72}}\\\\\rm\dfrac{\dfrac{7}{18}}{\dfrac{70}{72}}\\\\\rm\dfrac{\diagdown\!\!\!\!7}{\diagdown\!\!\!\!\!\!18}\cdot\dfrac{\diagdown\!\!\!\!\!\!72^4}{\diagdown\!\!\!\!\!\!70_{10}}=\dfrac{4\div2}{10\div2}=\dfrac{2}{5}\\\\\rm\dfrac{a}{b}=\dfrac{2}{5}\\\\\rm a+b=2+5=7\\\huge\boxed{\boxed{\boxed{\boxed{\rm\dagger\red{\maltese}~\blue{alternativa~A}}}}}\end{array}}$