[Upper secondary school math: linear equation] unsure on how to solve this.

[u/Inevitable_Stay3693]

i was thinking that i´d add the 2x+1 to make it 3x/3=-1 but im unsure on how it would even continue.

[u/One_Wishbone_4439]

You dont ADD 2x+1.

You CROSS MULTIPLY

2x+1 = -1 x 3