Question

a,(x+1)/3=2/6

b,(4-x)/-5=-5/(4-x)

c,3/(x+2)=5/(2x+1)

d,1/2=(x+1)/3x

e,-3/(x+1)=4/(2-2x)

Answer 1

a)\(\frac{x+1}{3}=\frac{2}{6}\)

=> \(\frac{x+1}{3}=\frac{1}{3}\)

=> x + 1 = 1 => x = 0

b) \(\frac{4-x}{-5}=\frac{-5}{4-x}\)

=> (4 - x)² = 25

=> (4 - x)² = 5²

=> 4 - x = 5 hoặc 4 - x = -5

=> x = -1 hoặc x = 9

c) \(\frac{3}{x+2}=\frac{5}{2x+1}\)

=> 3(2x + 1) = 5(x + 2) 

=> 6x + 3 = 5x + 10

=> 6x + 3 - 5x - 10 = 0

=> 6x - 5x + 3 - 10 = 0

=> 6x - 5x = 7

=> x = 7

d) \(\frac{1}{2}=\frac{x+1}{3x}\)

=> 3x = 2(x + 1)

=> 3x = 2x + 2

=> 3x - 2x - 2 = 0

=> x - 2 = 0

=> x = 2

e) \(\frac{-3}{x+1}=\frac{4}{\left(2-2x\right)}\)

=> -3(2 - 2x) = 4(x + 1)

=> -6 + 6x = 4x + 4

=> -6 + 6x - 4x - 4 = 0

=> -10 + 2x = 0

=> 2x = 10

=> x = 5