Answer:
13 inches
Step-by-step explanation:
First, you must remember that the perimeter of a shape is what you get when you add up all of the side lengths. With this information, and the fact that the problem has given us a perimeter of 30 inches and expressions for each side, it should be easy to form an equation of: 30=2x+3+4x-8+x. Now we just do the algebra...
1) Combine like terms: 30=2x+3+4x-8+x
30=7x-5
2) Add 5 to both sides: 35=7x
3) Divide both sides by 7: 5=x
Now you have a value for x (x=5). We can then plug in 5 for every instance of x. Our three side lengths are now:
5, 2(5)+3 ad 4(5)-8. If we simplify, our three side lengths become 5, 13 and 12. The question asks us for the longest side length, and out of the three this is 13. Therefore, our answer is 13 inches.
Hope this helps!