Answer:
Sonya pays a flat fee of $30 for her phone bill and pays $2 per gigabyte she uses per month. Put Sonya's bill as an equation with <em>d</em> being how many gigabytes she uses per month.
Step-by-step explanation:
We get the flat fee of $30 from "30 + 2d" and the $2 per gigabyte from "30 + 2d" and since we want to find out Sonya's total bill, that's where the + in "30 + 2d" comes from. We want the variable to be <em>d</em> therefore <em>d</em> is how many gigabytes she uses per month.
Answer:
x = 35
Step-by-step explanation:
Solve for x:
5 (x + 20) = 7 x + 30
Expand out terms of the left hand side:
5 x + 100 = 7 x + 30
Subtract 7 x from both sides:
(5 x - 7 x) + 100 = (7 x - 7 x) + 30
5 x - 7 x = -2 x:
-2 x + 100 = (7 x - 7 x) + 30
7 x - 7 x = 0:
100 - 2 x = 30
Subtract 100 from both sides:
(100 - 100) - 2 x = 30 - 100
100 - 100 = 0:
-2 x = 30 - 100
30 - 100 = -70:
-2 x = -70
Divide both sides of -2 x = -70 by -2:
(-2 x)/(-2) = (-70)/(-2)
(-2)/(-2) = 1:
x = (-70)/(-2)
The gcd of -70 and -2 is -2, so (-70)/(-2) = (-2×35)/(-2×1) = (-2)/(-2)×35 = 35:
Answer: x = 35
Answer:
781250 
Step-by-step explanation:
Let y is the length of the farm field
Let x is the width of the farm field
Given that, no fencing is necessary along the rock wall, so we can find the perimeter of the farm is:
2x + y = 2500 feet
<=> y = 2500 -2x
The are of the farm has the following formula:
A = x*y
<=> A = x(2500 - 2x)
<=> A = 2500x -2
To have the maximum area of field in square feet, we need to use differentials to estimate:
= 2500 - 4x
Set = 0, we have:
2500 - 4x = 0
<=> x = 625 feet.
=> y = 2500 - 2*625 = 1250 feet
So the maximum area of field is:
A = x*y = 625*1250 = 781250
Answer:
She had 15 minutes left.
Step-by-step explanation:
30 - 11 = 19
19 - 4 = <em>15</em>
