138+90+х+3•х=270+270 помогите

Question

138+90+х+3•х=270+270 помогите

Answer 1

4х=540-228;
4х=312;
х=78.

Answer 2

138+90+4х=540
228+4х=540
4х=540-228
4х=312
х=312:4
х=78