Question

qual e a fraçao que somada com 1 terço resulta em 1 setimo

Answer 1

$x+\frac{1}{3}=\frac{1}{7}\\ \\ x=\frac{1}{7}-\frac{1}{3}\\ \\ \boxed{x=\frac{3-7}{21}=-\frac{4}{21}}$

Answer 2

X+1/3=1/7
1/7-1/3
3-7/21=x
X=-4/3