Divide both sides by 3:
x^2-(22 x)/3+140/3 = 0
Subtract 140/3 from both sides:
x^2-(22 x)/3 = -140/3
Add 121/9 to both sides:
x^2-(22 x)/3+121/9 = -299/9
Write the left hand side as a square:
(x-11/3)^2 = -299/9
Take the square root of both sides:
x-11/3 = (i sqrt(299))/3 or x-11/3 = 1/3 (-i) sqrt(299)
Add 11/3 to both sides:
x = 11/3+(i sqrt(299))/3 or x-11/3 = 1/3 (-i) sqrt(299)
Add 11/3 to both sides:
Answer: | x = 11/3+(i sqrt(299))/3 or x = 11/3-(i sqrt(299))/3
