I need help with angles of a triangle

Question

The sum of the measures of two angles of a triangle is twice the measure of the third angle. The measure of the second angle is 28 degrees less than the measure of the third angle. What is the degree measurement of the medium angle?

Answer 1

I set up three relationships for three angles: A, B, and C

A+ B = 2C

     B=C-28

A+ B+C = 180

so I set up a 3 x 4 matrix and used the Gauss Jordan technique to solve for each angle. So the matrix becomes

A B C 

1  1  - 2  0

0  1  -1 - 28

1  1  1 1 80

solution came out to be A = 88, B = 32, C = 60

Answer 2

Let F, S & T be 3 angles, first, second and third

F+S=2T

S=T-28

That's 2 equations 3 unknowns. But there's a 3rd equation if this is a triangle: F+S+T=180

T+28+T-28+T=180

3T = 180

T =60

S=60-28=32

F=180-60-32=88

F,S,T = 88, 32, 60

Answer 3

x + y = 2z;z - y = 28 and x + y + z = 180, y = z - 28, x + z - 28 = 2z, x = z + 28;

z + 28 + z - 28 + z = 180; 3z = 180; z = 60°, y = 60 - 28 = 32° and x = 60 + 28 = 88°