"Find the cubic polynomial function with two of its zeros 2 and -3+√2 and a y-intercept of 7."

Answer: y = -0.5(x -2)(x^{2}+ 6x + 7)

I think that the function will look something similar to: y = k(x-2)(x-(-3+√2))^{2}

Then I would use the coordinates of the y-intercept (0,7) to find the value ofk. However, I'm not sure how to get "(x^{2}+ 6x + 7)".

Any suggestions would be appreciated, thank you!