y x 5+y x 8+4 x y+y+y x 2=20/3
y x(5+8+4+1+2)=20/3
y x 20=20/3
y =20/3:20
y =1/3
y x 5+y x 8+4 x y+y+y x 2=20/3
y x(5+8+4+1+2)=20/3
y x 20=20/3
y =20/3:20
y =1/3
y : \(\frac{2}{10}\)+ y : 12,56% + 4 : \(\frac{1}{y}\)+ y + y : 0,5 = \(\frac{20}{3}\)
y : 1/2 + y : 12.5% + 4 : 1/y + y + y : 1/5 = 20/3! ( Mấy bạn học sinh giỏi làm bài này, làm được cho 10 điểm nha hên! )
tìm y : a, 2 + \(\frac{3}{4-\frac{1}{2-y}}\)= 7
b, 16 : {\(\frac{\frac{3}{5}\cdot y+8}{21}+9\)} = \(\frac{7}{10}\)
DẤU Ở GIỮA 3/5 VÀ Y LÀ DẤU NHÂN
Tính\(y=\frac{2}{1+2}+\frac{2+3}{1+2+3}+\frac{2+3+4}{1+2+3+4}+...+\frac{2+3+4+...+20}{1+2+3+4+...+20}\)
Tìm Y, biết \(\left(y-\frac{1}{2}\right)\div\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+.....+\frac{1}{90}\right)=\frac{1}{3}\)
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+......+\frac{1}{y\times\left(y+1\right):2}=\frac{2009}{2011}\)
\(y.9,2+y:0,25-y.3,2=\frac{3}{4}.\left(1\frac{1}{2}-\frac{6}{8}\right)\)
\(Y:\frac{1}{2}+Y:\frac{1}{5}+Y:\frac{1}{4}+Y:\frac{1}{8}=190\)
Tìm y:
\(y:2\frac{1}{3}=1\frac{3}{4}:2\frac{1}{3}\)