Question

Tìm x:

a) \(\frac{3x-5}{x+4}=\frac{5}{2}\)

b) \(\frac{3x-1}{2x+1}=\frac{3}{7}\)

Answer 1

a) \(\frac{3x-5}{x+4}=\frac{5}{2}\)

<=> 2(3x-5) = 5(x+4)

<=> 6x-10 = 5x+20

<=> x = 30

b) \(\frac{3x-1}{2x+1}=\frac{3}{7}\)

<=> 7(3x-1) = 3(2x+1)

<=> 21x-7 = 6x+3

<=>15x = 10

<=> x = \(\frac{2}{3}\)

Answer 2

b) \(\frac{3x-1}{2x+1}=\frac{3}{7} \)

(3x - 1) . 7 = (2x + 1) . 3

21x - 7 = 6x + 3

21x - 6x = 3 + 7

15x = 10

=> x = \(\frac{2}{3}\)