Помогите решить уравнение (13х-63):7+86=90 

(13x-63):7=4
7*4=13x-63
13x=28+63
x=91:13

13х-63:7+86=90                                                                                                          13х=63:7+90-86                                                                                                          13х=9+4                                                                                                                13х=13                                                                                                                  х=13:13    х=1