Answer:
<em>Thus, the dimensions of the metal plate are 10 dm and 8 dm.</em>
Step-by-step explanation:
For a quadratic equation:

The sum of the roots is -b and the product is c. Note the leading coefficient is 1.
We know the perimeter of the rectangular metal plate is 36 dm and its area is 80 dm^2. Being L and W its dimensions, then:
P=2(L+W)=36
A=L.W=80
Note both formulas are closely related to the roots of the quadratic equation, we only need to adjust the data for the perimeter to be exactly the sum of L+W and not double of it.
Thus we use the semi perimeter instead as P/2=L+W=18
The quadratic equation is, then:

Factoring by finding two numbers that add up to 18 and have a product of 80:

The solutions to the equation are:
x=10, x=8
Thus, the dimensions of the metal plate are 10 dm and 8 dm.
Answer:
28.
Step-by-step explanation:
28 x 5 = 140
140 divided by 28 = 5.
5 hours.. 140 cupcakes. You divide the amount by the hours, showing you that 28 cupcakes per hour is the answer.
Answer:
(A) a=1,b=5,c=9
Step-by-step explanation:
We want to simplify
for values of a, b and c which satisfies: 
Converting our result to mixed fraction

Answer:
$879.19
Step-by-step explanation:
I'm not sure how you got that, but here's what I did.
To calculate tax:
Cost before tax * Tax% = Tax
$815.95 * 7.75% = $63.24
To calculate cost after tax:
Tax + Cost before tax = Cost after tax
$63.24 + $815.95 = $879.19