Here's a practice problem.

Given the lines

x = (1,2,-1) + t(3,1,2)

y = (9,0,1) + s(-1,2,1)

a) determine whether they intersect

b) if they intersect find the equation of the plane determined by the lines

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Could somebody check my answer please?

I have decided that they do intersect==> -3x - 5y + 7z + 20 = 0