First blank: Substitution or transitive property of equality
Second blank: Subtraction property of equality
Answer:

Step-by-step explanation:
The formula that is used to calculate the area of a rectangle is:

Where "l" is the lenght and "w" is the width.
You know that the area of that rectangle is:

And, according to the exercise, its lenght is 7 more than its width; then:

Then, you can make the corresponding substitution into the formula
:

Simplify:

Factor the equation. Find two numbers whose sum is 7 and whose product is -744. These are 31 and -24.
Then, you get:

The width of the rectangle is the positive value:

Then, the lenght is:

Based on the information, Christian would have $5525.5 of an annuity.
<h3>How to calculate the annuity?</h3>
According to the given information, the number of coffees per week is 3 then, per month is 3x4 = 12
Each coffee is $4.5. Then monthly expenditure for coffees is 12 x 4.5 = $54
Rate of interest r = 1.6% = 1.6/100 = 0.016 and for monthly compounding r = 0.016/12 = 0.00133
n = number of payments = 8 x 12 = 96
We can use the formula for finding the future value as below
FV = C x [ ( 1 + r )n-1 ] / ( r )
FV = 54 x [ ( 1 + 0.00133 )96 – 1 ] / (0.00133)
= 54 x [ (1.13609 - 1)] / (0.00133)
= 54 x 0.13609 / (0.00133)
= 54 x 102.3233
= 5525.5
Therefore Christian would have $5525.5 of the annuity.
Learn more about annuity on:
brainly.com/question/5303391
#SPJ1