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
Answer:
3 subtracted from the product of 7 and a number b
3 subtracted= -3
product of 7 and a number b= 7b
put those together:
7b-3
hope this helps, also what grade is this
Answer:
The simplified form of r^-7 + s^-12 is ----> 1/r^7 + 1/s^12
Step-by-step explanation:
F(-2)+g(5) = 3(-2) -1 + (-5) + 6
f(-2)+g(5) = -6 -1 - 5 + 6
f(-2)+g(5) = -6
Answer:
three million
Step-by-step explanation:
