Five-sevenths of a number is -35. what is the number?

So lets write this equation out.  Let x be that number we are trying to find. 

So five-sevenths is a fraction that is written like this 

5/7 

when you see the word "of" that means multiplication 

so we can write the full equation. 

(5/7)x = -35 

now we can solve 

Multiply both sides by 7 

5x = -245

now divide by 5 
and we get 

x = -49