when x intercept -3, point P(2,5,7) and Q(1,10,14) how to find x,y and z?

What do you mean by "finding" x,y,z?

(x-2)/-1 = (y-5)/5 = (z-7)/7

or

x = 2-t
y = 5+5t
z = 7+7t

When x = -3, t=5, so the line passes through (-3,30,42)