Question

4. giải các phương trình sau

a) 7x-3/ x-1 = 2/3

b) 2(3-7x)/1+x=1/2

Answer 1

\(\dfrac{7x-3}{x-1}=\dfrac{2}{3}\) (x\(\ne\)1)

\(\Leftrightarrow\) 3(7x - 3) = 2(x - 1)

\(\Leftrightarrow\) 21x - 9 = 2x - 2

\(\Leftrightarrow\) 21x - 2x = 9 - 2

\(\Leftrightarrow\) 19x = 7

\(\Leftrightarrow\) x = \(\dfrac{7}{19}\)

Vậy.........................

b) \(\dfrac{2\left(3-7x\right)}{1+x}=\dfrac{1}{2}\) (x \(\ne\)-1)

\(\Leftrightarrow\) 4(3 - 7x) = 1 + x

\(\Leftrightarrow\) 12 - 28x = 1 + x

\(\Leftrightarrow\) -28x - x = -12 + 1

\(\Leftrightarrow\) -29x = -11

\(\Leftrightarrow\) x = \(\dfrac{11}{29}\)

Vậy..................