Question

Numarul - 2 supra 7 mimusul este in naintea liniei de fractie este solutie a ecuatiei :
A. 2x-7=0. B. 7x+3=5. C. 7x+2=0. D.9x-3=2x

Answer 1

Luam fiecare caz:
a. 
$2* (- \frac{2}{7} ) - 7=0 =\ \textgreater \ - \frac{4}{7} -7=0 =\ \textgreater \ \frac{-4-49}{7}=0 =\ \textgreater \ \frac{-53}{7}=0 (F)$
b.
$7*(- \frac{2}{7} )+3 =5 =\ \textgreater \ -2+3=5 =\ \textgreater \ 1=5 (F)$
c.
$7*(- \frac{2}{7} )+2 = 0 =\ \textgreater \ -2+2=0 =\ \textgreater \ 0=0 (A)$
d.
$9*(- \frac{2}{7} )-3 = 2* (- \frac{2}{7} ) =\ \textgreater \ - \frac{39}{7} = - \frac{4}{7} (F)$

Deci $-\frac{2}{7}$ este solutie pentru C. 7x+2=0