Here is you answer , happy today
5, it says that the range is 5 so you count five across the chart from the first point of data

Simplifying
36c2 + -84cd + 49d2 = 0
Reorder the terms:
-84cd + 36c2 + 49d2 = 0
Solving
-84cd + 36c2 + 49d2 = 0
Solving for variable 'c'.
Factor a trinomial.
(6c + -7d)(6c + -7d) = 0
Subproblem 1
Set the factor '(6c + -7d)' equal to zero and attempt to solve:
Simplifying
6c + -7d = 0
Solving
6c + -7d = 0
Move all terms containing c to the left, all other terms to the right.
Add '7d' to each side of the equation.
6c + -7d + 7d = 0 + 7d
Combine like terms: -7d + 7d = 0
6c + 0 = 0 + 7d
6c = 0 + 7d
Remove the zero:
6c = 7d
Divide each side by '6'.
c = 1.166666667d
Simplifying
c = 1.166666667d
Subproblem 2
Set the factor '(6c + -7d)' equal to zero and attempt to solve:
Simplifying
6c + -7d = 0
Solving
6c + -7d = 0
Move all terms containing c to the left, all other terms to the right.
Add '7d' to each side of the equation.
6c + -7d + 7d = 0 + 7d
Combine like terms: -7d + 7d = 0
6c + 0 = 0 + 7d
6c = 0 + 7d
Remove the zero:
6c = 7d
Divide each side by '6'.
c = 1.166666667d
Simplifying
c = 1.166666667d
Solution
c = {1.166666667d, 1.166666667d}
<h2>I HOPE IT HELPS ♥️</h2>
B.) the length of the spring increases by 0.006 cm for every gram added to it.
y = 0.006x + 11.50
where:y = length of the spring in centimetersx = mass added to the spring in grams11.50 = the first number in the sequence0.006 = the common difference among numbers in the sequence.
x y1 11.5 + 0.006(1) = 11.50 + 0.006 = 11.506 2 11.5 + 0.006(2) = 11.50 + 0.012 = 11.5123 11.5 + 0.006(3) = 11.50 + 0.018 = 11.5184 11.5 + 0.006(4) = 11.50 + 0.024 = 11.5245 11.5 + 0.006(5) = 11.50 + 0.030 = 11.530
For every 1 gram added, the length of the string increases by 0.006cm
hope this helps
Ummmm he burned a lot of calories lol