Sajia can sell 21 books she can sell if she comes back on sunday and the required inequality is 
<em><u>Solution:</u></em>
Given that Sajia has 30 Books in her library
She sold 9 books at the thrift store on Saturday
To find: We have to write and solve an inequality to determine number of more books she can sell if she comes back on sunday
Let "x" be the number of more books she can sell if she comes back on sunday
<em><u>We can write a inequality as:</u></em>


Now moving 9 from L.H.S to R.H.S we get,

On solving 30 - 9 = 21,

So Sajia can sell 21 books she can sell if she comes back on sunday
Second one if you distribute the first expression you get the second equation so the expressions are equivalent
From 55 mph to 70 mph is a 36% increase.
I hope this helped!