Find x value

1. If \(\frac{1}{7}=\frac{4}{x+1}\), what is the value of \(x\)?

  1. 14
  2. 27
  3. -12
  4. 8
  5. 12

Multiply the left side by \(\frac{x+1}{x+1}\) and the right side by \(\frac{7}{7}\)


$$\frac{x+1}{x+1} \cdot \frac{1}{7}=\frac{4}{x+1}\cdot\frac{7}{7}$$


$$\frac{x+1}{7(x+1)}=\frac{4\cdot7}{7(x+1)}$$


The denominators can now cancel each other


$$x+1=28$$


Subtract 1 from both sides


$$x+1-1=28-1$$


$$x=27$$


The answer: B