The square of a binomial expands as follows:

Expanding all the binomials, we have

Sum like terms:

Simplify terms appearing on both sides:

Move all terms involving k to the left and all numbers to the right:

Divide both sides by -20:

Answer:
165.6
Step-by-step explanation:
165.6 is 72% of 230
Twice a number (2x) decreased by 7 (- 7).
2x - 7
Two times a specfic number (x) subtracted by 7.
Hello from MrBillDoesMath!
Answer:
Top line: y = (2/3)x + 2
Bottom line: y = (2/3)x -1
Discussion:
The graph provided is hard to read but I did the best I could.
The top line appears to pass through the points (0,2) and (-3,0)
For this line
m = change y /change x = (0-2)/(-3-0) = -2/-3 = +2/3. So
y = mx + b => y = (2/3) x+ b. As the line passes through (0,2) set x = 0, y= 2 in y = (2/3)x + b =>
2 = (2/3) 0 + b => b = 2
Therefore y = (2/3)x + 2
The bottom line appears to pass through the points (0,-1) and (3,1)
For this line
m = change y /change x = (1-(-1)) /(3-0) = +2/-3. So
y = mx + b => y = (2/3) x+ b. As the line passes through (0,-1) set x = 0, y= -1 in y = (2/3)x + b =>
-1 = (2/3) 0 + b => b = -1
Therefore y = (2/3)x + -1
Thank you,
MrB