Answer:
240 centimeters
Step-by-step explanation:
multiply the length value by 100
4s+7a=861
s+a=168
This can be solved using either elimination or substitution. I am going to use substitution.
Solve s+a=168 for s
s=168-a
Replace 168-a for s in 4s+7a=861
4(168-a)+7a=861
672-4a+7a=861
Solve for a
672+3a=861
3a=189
a=63
Substitute 63 for a in s=168-a
s=168-63=105
So, s=105 student tickets and a=63 adult tickets
She forgot about the final x at the end, because the first expression is 3x+6+x, and the second one is 3(x+2). The second one expands to 3x+6, but it doesn't have the final term at the end.
Also, 3 is not really a factor of x (technically it could be because x in unknown, but in terms of like terms and stuff it isn't) so you can't take a 3 out of x (unless you leave it as 1/3x I guess).
Anyway, yeah she forgot about the final x and therefore the factor she took out is incorrect anyway. She also could've simplified the first expression so that it became 4x + 6
