X = 213.075
First you have to get rid of the 4 and since it’s multiplying you to the opposite and that’s dividing.
-3.7 divided by 4 = -0.925
X - 214 = -0. 925
Then you add 214 to -0.925 and get 213.075
The complete factor from:
2x3 + 6x2 + 10x + 30
2x(x+3) + 10(x+3)
(x+3)(2x+10)
2(x+5)(x+3)
hope this help