Simplify the expression: 7r–3r+9r
2 answers:
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Answer:
1. x = +/- 2 - 7
2. x = +/-
3. n = +/-
Step-by-step explanation:
1. Divide both sides by 2: (x + 7)^2 = 8
Square root both sides: x + 7 = +/- 2
Subtract 7 from both sides: x = +/- 2 - 7
2. Square root both sides: x - 3 =
Since there is a negative inside the radical, we need to have an imaginary number: . So,
Add 3 to both sides: x = +/-
3. Divide by -5 from both sides: (n - 2)^2 = -2
Square root both sides: n - 2 =
Again, we have to use i:
Add 2 to both sides: n = +/-
Hope this helps!
Answer:
1) For 450 minutes of calling the two plans cost the same.
2) The cost when the two plans cost the same is $56.5.
Step-by-step explanation:
The cost of both plans can be modeled by linear functions.
Plan A:
$25 plus an additional $0.07 for each minute of calls.
So, for t minutes of calls, the cost is:
Plan B:
$16 plus an additional $0.09 for each minute of calls.
So, for t minutes of calls, the cost is:
Q1: For what amount of calling do the two plans cost the same?
This is t for which:
For 450 minutes of calling the two plans cost the same.
Q2: What is the cost when the two plans cost the same?
This is A(450) or B(450), since they are the same.
The cost when the two plans cost the same is $56.5.