I think it is 90
Hope this help you?!
1000 + 50x = 500 + 75x
First move 500 by subtracting it from 1000.
500 + 50x = 75x
Now subtract 50x from 75x.
500 = 25x
Then divide 500 by 25.
20 = x
They would've saved the same amount($2,000) on the 20th week.
Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :
<span> 5*(x-2)-4*(x+1)-(50)=0 </span>