R=x(A+B)
divide both sides by x
R/x=A+B
minus B both sides
(R/x)-B=A
A=(R/x)-B
X-x-2/6=x-7/3+2/3
-2/6+7/3-2/3=x
x= -2/6+5/3
x= 8/6
x= 4/3
B. 31°, 43°, 106°
since all angles of a triangle add up to 180°, you combine all of the equations to equal 180 and solve for X. the equation you would get it 3x+1+11x-4+5x-7=180. this simplifies to 19x-10=180. then you solve for x, and it is 10. then, you plug 10 into all of the equations separately to find the angles. therefore, the answer is B
See the attachment..........
They can line up 20 different ways