My friend... My method wasn't wrong and I couldn't find any mistake on my procedure... Check it out and analyze it by yourself...
Let:
x = Chemistry textbooks sold
y = Physics textbooks sold
The textbook store sold a combined total of 260, so:

The number of chemistry books sold was three times the number of physics textbooks sold, so:

Let:

Replace (2) into (1):

Replace the value of y into (2):
Answer:
x = -7 ±3i
Step-by-step explanation:
(x+7)^2+9=0
Subtract 9 from each side
(x+7)^2+9-9=0-9
(x+7)^2=-9
Take the square root of each side
sqrt((x+7)^2) = ±sqrt(-9)
We know sqrt(ab) = sqrt(a) sqrt(b)
x+7 = ±sqrt(-1) sqrt(9)
We know that sqrt(-1) is the imaginary number i
x+7 = ±i *3
x+7 =±3i
Subtract 7 from each side
x+7-7 = -7 ±3i
x = -7 ±3i
W² - v + 1
(-2)² - (-8) + 1
4 + 8 + 1 = 13
B.13 is your answer
(two negatives = one positive)*
(plug in -2 for w, and -8 for v)
(is that w², or do you mean 2w?)
hope this helps