# Algebra

posted by on .

Hi, here is a question and my answer I have done so far, not sure about the end result so any help appreciated

5a-2 (5+4a)=-9
Multiply out brackets 5a-10+8a =-9
Collect like terms 13a = -9
Divide by 13 = a =1/13
I am pretty sure the answer should be a = -1/3 but not sure how to get there, , thanks

• Algebra - ,

You have an error in your first step when you multiplied:
-2(5 + 4a)
It is not -10 + 8a .

• Algebra - ,

Salisbury High School decided to take their students on a field trip to a theme park. A total of 150 people went on the trip. Adults pay \$45.00 for a ticket and students pay \$28.50 for a ticket. How many students and how many adults went to the park if they paid a total of \$4770

• For Lily - ,

Please do not append a new question at the end of somebody else posting.

Your question will likely be passed over, since most tutors will not look at a posting if they see that it has been answered.

let number of adult tickets be a
let number of student tickets be 150-a

solve:
45a + 28.5(150-a) = 4770