This would be your answer
Answer:The number of minutes that Alexandra talked on her cell phone is 120
Step-by-step explanation:
A cell phone company charges a flat rate of 4.75 per month with an additional charge 0.19 per minute. Assuming the total number of minutes of call made for the month is represented by x and the total cost of x minutes of call is y, then
y = 0.19x + 4.75
To determine how many minutes that Alexandra talked on her cell phone if his monthly bill was 27.55, we would substitute y = 27.55 into the equation. It becomes
27.55 = 0.19x + 4.75
0.19x = 27.55 - 4.75 = 22.8
x = 22.8/0.19 = 120 minutes.
Answer:
8.9
Step-by-step explanation:
Part B seems to be missing, but I think I have enough information to be able to answer.
Let's say we had two numbers x and y. Let x be rational and y be irrational.
If x is some nonzero number, then x*y is irrational. The proof for this is a bit lengthy so I'll leave it out.
For instance,
x = 2 is rational, y = sqrt(3) is irrational, x*y = 2*sqrt(3) is irrational.
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If we made x = 0, then
x*y = 0*y = 0
This is true for any value of y that we want. The y value doesnt even have to be irrational. It can be any real number.
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So the distinction is that if x = 0, then x*y = 0 is rational since 0 is rational. Otherwise, x*y is irrational.