Answer:
- The system of equations is x + y = 85 and 7/20x+2/5y=31
- To eliminate the x-variable from the equations, you can multiply the equation with the fractions by 20 and multiply the other equation by -7.
- B-She used 60 minutes for calling and 25 minutes for data.
Step-by-step explanation:
It is always a good idea to start by defining variables in such a problem. Here, we can let x represent the number of calling minutes, and y represent the number of data minutes. The the total number of minutes used is ...
x + y = 85
The total of charges is the sum of the products of charge per minute and minutes used:
7/20x + 2/5y = 31.00
We can eliminate the x-variable in these equations by multiplying the first by -7 and the second by 20, then adding the result.
-7(x +y) +20(7/20x +2/5y) = -7(85) +20(31)
-7x -7y +7x +8y = -595 +620 . . . . eliminate parentheses
y = 25 . . . . . . . . simplify
Then the value of x is
x = 85 -y = 85 -25
x = 60
X^3 -2x^2 -35x
=x(x^2-2x-35)
=x(x-7)(x+5)
Find the last angle:
180-(30+90)
180-(120)
60
Evaluate using sine rule:
=
c=
=
=20
The length of line segment AB is 20 feet (answer choice C)
Answer:
Three solutions.
Step-by-step explanation:
In order to solve system of equations by graphical method, we graph the system of equations. The intersection point (s) of the two graph would give us the solution.
If the graph of the equations intersect at 2 points then there will be 2 solutions, if there are 4 intersection then there would be 4 solutions and so on.
For the given graph, we can see that there are three intersection points.
Hence, there would be three solutions.
