In a certain county, the number of charter schools is eleven less than twice the number of alternative schools. there are 35 charter schools in the county. which of the following equations would you use to find the number of alternative schools, a, in the county?

Hey!
Here is the equation set up. 
35 = 2a-11
because it says eleven less than the 2a, so that's why its 2a and then the minus 11
You'd probably use this equation, but im not sure what answer choices you received. 
Then to find a you would add 11 to both sides and divide by 2 to get 23
or you could divide by 2 first having you with 17.5 = a - 5.5 and then add 5.5 to both sides to get 23 as well
Hope this helps!