Answer:
l = 24ft
Step-by-step explanation:
A = lw
360 = (x + 9)(x)
360 = x^2 + 9x
0 = x^2 + 9x - 360
0 = (x + 24)(x - 15)
x ≠ -24 (length cannot be negative)
x = 15
l = 15 + 9
l = 24ft
5 sig figs is the correct answer
We can solve this by substitution method.
Look at the second equation. If we rearrange to find 7x, we can substitute in the value into the first equation.



Therefore, 
Now replace the 7x in the first equation with 5y - 12:
(substitute in 7x = 5y - 12)




Now that we know y, we can find x by substituting in y = 1 into any equation we want. I will use the equation: 7x = 5y - 12
(substitute in y = 1)




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Answer:
D
Step-by-step explanation: 3x8=24 t-shirts
3x2=6 packs
24+6=30$