You're trying to find constants

such that

. Equivalently, you're looking for the least-square solution to the following matrix equation.

To solve

, multiply both sides by the transpose of

, which introduces an invertible square matrix on the LHS.

Computing this, you'd find that

which means the first choice is correct.
Answer:
B = 38°
Step-by-step explanation:
A straight angle is 180°. If your four angles total a straight angle, then ...
60 +2x +3x +25 = 180
95 = 5x . . . . . . subtract 85
x = 19 . . . . . . divide by 5
2x = 38 . . . . . angle B is 38°