Please! In the rectangular coordinate system, the points a (2a, a + B-1), B (- B, A-1) are symmetric about the origin, so find the value of a + B It's a process! Please, please!

Please! In the rectangular coordinate system, the points a (2a, a + B-1), B (- B, A-1) are symmetric about the origin, so find the value of a + B It's a process! Please, please!

The sum of the coordinates of the two points symmetrical about the origin is (0,0);
That is: 2a-b = 0 and a + B-1 + A-1 = 0, 2A + B = 2
∴a=0.5,b=1
b=1.5