Answer: The answer is 8.
Step-by-step explanation: The first step is to convert the expression into figures. We shall call the unknown number Y. So if we are told “the square of a number,” that means Y squared, or better still, Y^2. Further we are told “the difference between the square of a number and 40” and that can be written as;
Y^2 - 40.
Next we are told that this expression is equal to 3 times that number (that is 3Y). That can now be written out as follows,
Y^2 - 40 = 3Y
If we move all expressions to one side of the equation, what we would have is,
Y^2 - 3Y -40 = 0
(Remember that when a positive value crosses to the other side of an equation it becomes negative and vice versa)
We now have a quadratic equation
Y^2 -3Y - 40 = 0
By factorizing we now have
(Y -8) (Y + 5) = 0
Therefore Y - 8 = 0 or
Y + 5 = 0
Hence, Y = 8 or Y = -5
Since we are asked to calculate the positive solution, Y = 8
Answer:
Step-by-step explanation:
(-3, 2)
Horizontal is y = 2
Vertical is x = -3
In the same way (1, 4) is
y = 4
x = 1.
The cost to drive such a car 12,000 miles in 2012 was 7560
<em><u>Explanation</u></em>
The average cost of driving a medium sedan in 2012 was 0.63 per mile.
Now for finding the total cost to drive such a car, we need to <u>multiply the 'cost per mile' by the 'total number of miles'</u>.
So, total cost to drive 12000 miles 
