Since we are trying to find the adult seats, we'll set that to x. Now the student section is 2x + 25. The total seats is 130 which is the student section and adult section added together. So now we can write an equation from the information given...
Students + adults = 130
(2x + 25) + x = 130
2x +25 +x = 130
2x + x + 25 = 130
3x + 25 = 130
3x = 130 - 25
3x = 105
x = 105/3 = 35
So there are 35 adult seats (remember we set adults to x)
Now we substitute back into the equation to find the students seats. As you recall students = 2x + 25
Students = 2x + 25
Students = 2(35) + 25
Students = 70 + 25
Students = 95
There are 95 student seats and 35 adult seats.
