Đáp án + Giải thích các bước giải:
a)
`x/10=(-7)/(-y)=(-4)/8`
`to x/10=7/y=-1/2`
`+) \ x/10=-1/2 to 2x=-10 to x=-5`
`+) \ 7/y=-1/2 to y=-14`
Vậy `(x;y)=(-5;-14)`
b)
`|-2x+1/(-3)|=8/6=4/3`
`to` \(\left[ \begin{array}{l}-2x+\dfrac{1}{-3}=\dfrac{4}{3} \\ -2x+\dfrac{1}{-3}=-\dfrac{4}{3}\end{array} \right.\)`to`\(\left[ \begin{array}{l}-2x=\dfrac{4}{3}-\dfrac{1}{-3}\\-2x=-\dfrac{4}{3}-\dfrac{1}{-3}\end{array} \right.\)
`to`\(\left[ \begin{array}{l}-2x=\dfrac{5}{3}\\-2x=-1\end{array} \right.\)`to` \(\left[ \begin{array}{l}x=-\dfrac{5}{6}\\x=\dfrac{1}{2}\end{array} \right.\)
Vậy `x in {-5/6;1/2}`
