Answer:
A quadratic equation can be written as:
a*x^2 + b*x + c = 0.
where a, b and c are real numbers.
The solutions of this equation can be found by the equation:

Where the determinant is D = b^2 - 4*a*c.
Now, if D>0
we have the square root of a positive number, which will be equal to a real number.
√D = R
then the solutions are:

Where each sign of R is a different solution for the equation.
If D< 0, we have the square root of a negative number, then we have a complex component:
√D = i*R

We have two complex solutions.
If D = 0
√0 = 0
then:

We have only one real solution (or two equal solutions, depending on how you see it)
S would be the annual sales of the electronic device. In this case, that number is in the millions.
Therefore, our 13.9 becomes 13.9 millions.
Or written out, it would be: 13,900,000
A community group bought 30 tickets to an amusement park at a total cost of $810. They bought x student tickets for $25 each and y adult tickets for $30 each.
***
let x=number of student tickets bought
30-x=number of adult tickets bought
..
25x+30(30-x)=810
25x+900-30x=810
5x=90
x=18
30-x=12
number of student tickets bought=18
number of adult tickets bought=12
Hope this helps!
Answer: $825 (B)
Step-by-step explanation:
it’s obvious
Answer:
A
Step-by-step explanation:
You can write an expression to represent the total cost of a pair of shoes. The price of the shoes is the variable r. The shoes are marked down 20% or 0.2r. So the new price of the shoes will be r - 0.2r. You will also have to pay a tax of 5% or 0.05 of the new price. This is written as 1.05(r - 0.2r). You can simplify it by doing whats in the parenthesis.
1.05(r - 0.2r) = 1.05r(0.8r) = 0.84r