We have a square garden of 400 square foot.
The area of a square is:

where x: side length.
In this case:
![\begin{gathered} A=400=x^2 \\ x=\sqrt[]{400}=20\text{ ft} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20A%3D400%3Dx%5E2%20%5C%5C%20x%3D%5Csqrt%5B%5D%7B400%7D%3D20%5Ctext%7B%20ft%7D%20%5Cend%7Bgathered%7D)
The perimeter of the square is the sum of the lengths of the sides of the square. As they are all equal, we can write:

The fencing is priced at $1.50 per foot. If we add the 7% sales tax to this price we get:

The fencing will be installed in all the perimeter (80 ft).
We can calculate the total cost by multiplying the sales price ($1.605 per foot) and the perimeter (80 ft):

Answer: the fencing will cost a total of $128.40
Ok. so lets call the cost of each soda x. now, 3 packs of soda is 10 less than five packs of soda. so the price of 3 packs of soda is 3x, the price of five packs is 5x. now, it says that 3 packs is 10 less than five packs. that means that 3x=5x-10.
now, to find the price of a pack of soda, we have to isolate x.
add 10 to both sides to get 3x+10=5x. now, we subtact 3x on both sides to get 10=2x. divide by 2 on both sides, x=5. a pack of soda is 5 dollars
Complete the square:
<span>y = 3x^2 - 12x + 4 </span>
<span>y = 3(x^2 - 4x) + 4 </span>
<span>y = 3(x^2 - 4x + 4 - 4) + 4 </span>
<span>y = 3(x^2 - 4x + 4) - 12 + 4 </span>
<span>y = 3(x - 2)^2 - 8</span>