Question

21) Calcule O Valor Numérico das Expressões

Answer 1

$a)\\\\Valor~numerico:\\ \\ a+b~para~a=\frac{1}{3}~e~b=-\frac{1}{5} \\ \\ \frac{1}{3} +(-\frac{1}{5})~+~com~-=-\\ \\ \frac{1}{3} -\frac{1}{5} \\ \\ m.m.c.=15\\ \\ \frac{5-3}{15} =\frac{2}{15} \\ \\ b)\\ \\ 2x-y~para~x=7~e~y=-\frac{1}{2} \\ \\ 2.7-(-\frac{1}{2} )~-~com~-=+\\ \\ 14+\frac{1}{2} \\ \\ m.m.c.=2\\ \\ \frac{28+1}{2} =\frac{29}{2}$

$c)\\ \\ x^{2} -yz~para~x=\frac{1}{2} ,~y=\frac{1}{3} ~e~z=\frac{1}{4} \\ \\ (\frac{1}{2} )^{2} -\frac{1}{3} .\frac{1}{4} \\ \\ \frac{1}{4} -\frac{1}{12} \\ \\ m.m.c.=12\\ \\ \frac{3-1}{12} =\frac{2}{12} =\frac{1}{6}$