Answer: x = 6 plus-or-minus 3 StartRoot 10
Step-by-step explanation:
The given quadratic equation is expressed as
x² - 12x + 36 = 90
Rearranging the equation so that it takes the the standard form of
ax² + bx + c, it becomes
x² - 12x + 36 - 90 = 0
x² - 12x - 54 = 0
The general formula for solving quadratic equations is expressed as
x = [- b ± √(b² - 4ac)]/2a
From the equation given,
a = 1
b = - 12
c = - 54
Therefore,
x = [- - 12 ± √(- 12² - 4 × 1 × - 54)]/2 × 1
x = [12 ± √(144 + 216)]/2
x = [12 ± √360]/2
x = (12 ± 6√10)/2
x = 6 + 3√10
The
<u>correct answer</u> is:
Matthew's rate is higher by $50 per month.
Explanation:
We know that Christopher's rate is $550 per month.
To find Matthew's rate, we will treat the data we have as ordered pairs:
(3, 1800)
(6, 3600)
(9, 5400)
We find the slope of the line between these points. The formula for slope is:

Using the first two points, we have:

To verify Matthew saves the same amount each month, we will find the slope between the second two points and make sure they're the same:

Matthew's rate is $600 per month.
This is higher than Christopher's by 600-550=$50 per month.