Question

Tìm các số nguyên x,y biết:

a)\(\frac{x-1}{-3}=\frac{4}{7}\)

b)\(\frac{2}{x}=\frac{y+1}{-9}\)

Answer 1

a)\(\frac{x-1}{-3}=\frac{4}{7}\)

\(\Leftrightarrow7x-7=-12\)

\(\Leftrightarrow7x=-12+7\)

\(\Leftrightarrow7x=-5\)

\(\Leftrightarrow x=\frac{-5}{7}\)

vì \(x\in Z\Rightarrow x\in\left\{\varnothing\right\}\)

b) \(\frac{2}{3}=\frac{y+1}{-9}\)

\(\Leftrightarrow3y+3=-18\)

\(\Leftrightarrow3y=-18-3\)

\(\Leftrightarrow3y=-21\)

\(\Leftrightarrow y=-7\)

hok tốt!!