Solve 4 - 2(-5a - 10)=30 and justify each step

First you would do parenthesis according to the PEMDAS(Parenthesis, Exponents, Multiply, Divide, Add, Subtract) Rule

4 -2(-5a -10) = 30

4 + 10a + 20 = 30

Now you need to add 4 and 20 because they are on the same side

24 + 10a = 30

Now subtract 24 on both sides

24 + 10a = 30

-24. -24

10a = 6

Last divide 10 from both sides

10a/10. = 6/10

a= 6/10

Last simplify (optional but recommended)

a = 3/5 or 0.6

Hope this helped :)

A = 0.6

10 will be the number of adult tickets and 11 will be the number of children tickets. i hope i could ! good luck : )