Ta có :

\(x+\left(\dfrac{-31}{12}\right)^2=\left(\dfrac{49}{12}\right)^2-x\)

\(\Rightarrow2x+\dfrac{31^2}{12^2}=\dfrac{49^2}{12^2}\Rightarrow2x=\dfrac{49^2-31^2}{12^2}=10\)

\(\Rightarrow x=5\)

\(\Rightarrow y^2=\left(\dfrac{49}{12}\right)^2-5=\dfrac{1681}{144}\)

\(\Rightarrow y=\dfrac{41}{12}\)

Bài làm:

Ta có: \(x+\left(-\frac{31}{12}\right)^2=\left(\frac{49}{12}\right)^2-x\)

\(\Leftrightarrow2x=\frac{2401}{144}+\frac{961}{144}\)

\(\Leftrightarrow2x=\frac{1681}{72}\)

\(\Rightarrow x=\frac{1681}{144}\)

=> \(y^2=\frac{1681}{144}+\frac{961}{144}=\frac{2642}{144}\)

=> \(y=\pm\frac{\sqrt{2642}}{12}\)

\(x+\left(\frac{-31}{12}\right)^2\left(\frac{49}{12}\right)^2-x=y\)

\(x+\frac{961}{144}.\frac{2401}{144}-x=y\)

\(x+\frac{2307361}{20736}-x=y\)

\(y=\frac{2307361}{20736}\)

         Thay vào \(x+\frac{961}{144}.\frac{2401}{144}-x=y\) ta được

\(x+\frac{2307361}{20736}-x=y\)

\(x-x+\frac{2307361}{20736}=\frac{2307361}{20736}\)

Vậy x thuộc N;\(y=\frac{2307361}{20736}\)

\(\Leftrightarrow\left(x-x\right)+\frac{961}{144}\cdot\frac{2401}{144}=y\Leftrightarrow y=\frac{2307361}{20736}\)

\(\Rightarrow x\in R\)

( hình như đề sai :v )

đề saI

​

X+(-31/12)^2 = (49/12)^2 -x=y

(-31/12)^2 - (49/12)^2 = -x-x = y

961/144 - 2410/144 = -2x

-10=-2x

10=2x

10:2=x

5=x

X+961/144=y^2

5+961/144=y^2

1681/144=y^2

=>y=41/144

Dấu phân số mình ký hiệu là / đó nha

x+(-31/12)^2=(49/12)^2-x

x+x=(49/12)^2-(-31/12)^2

tính x

từ x tìm ra y

b)x(x-y):[y(x-y)]=3/10:(-3/50)=...

=>x/y=... =>x=...;y=...