a ) x = 1 9 + 5 7 = 52 63 b ) x = 2 15 − 3 10 = − 1 6

c ) x = 2 45 − 1 9 = − 1 15 ; d ) x = − 3 7 − 4 5 − − 2 3 = − 59 105

a)  x = 1 9 + 5 7 = 52 63

b)  x = 2 15 − 3 10 = − 1 6

a) \(\frac{2}{5}-\frac{2}{5}x+\frac{1}{3}=x-\frac{7}{15}\)

\(\Leftrightarrow\frac{11}{15}-\frac{2x}{5}=x-\frac{7}{15}\)

\(\Leftrightarrow\frac{2x}{5}=x-\frac{7}{15}-\frac{11}{15}\)

\(\Leftrightarrow-\frac{2x}{5}=x-\frac{5}{6}\)

\(\Leftrightarrow-\frac{2x}{5}=x.5-\frac{5}{6}.5\)

\(\Leftrightarrow-2x=5x-6\)

\(\Leftrightarrow-2x=-5x-6-5x\)

\(\Leftrightarrow-7x=-6\)

\(\Rightarrow x=\frac{6}{7}\)

\(7:\frac{5.8.x-57}{19+3}=7.\frac{22}{40x-57}=1775\)

<=> \(\frac{154}{40x-57}=1775=>x=\frac{154+1775.57}{40}\)

18B

19B

Đề có đúng không bạn?

\(57+\left(7-32\right)=319-\left(x+3^{19}\right)\\ \Rightarrow57-25=319-\left(x+3^{19}\right)\\ \Rightarrow32=319-\left(x+3^{19}\right)\\ \Rightarrow287=x+3^{19}\\ \Rightarrow x=3^{19}-287\)

X x 10 - X = 207

X x (10 - 1) = 207

X x 9 = 207

X = 207 : 9

X = 23

\(x\times10-x=207\)

\(x\times\left(10-1\right)=207\)

\(x\times9=207\)

\(x=207:9\)

\(x=23\)

Ai đó trả lời dùm đc khoog ạ ?

\(\frac{x}{19}<\frac{7}{57}\)

Ta có \(\frac{x}{19}=\)\(\frac{x.3}{19.3}=\frac{x.3}{57}\)

=> x = 0;1;2

0;1;2 toi nghi vay

1;2;3

X nằm trong khoảng tu 0 den 7/3 because X<(7x100)/57