1) х
2) 90-х
х-1/4х=90-х+1/4х
3/4х=90-3/4х
3/4х+3/4х=90
6/4х=90
х=90:6/4
х=90*4/6=60 в первой
90-60=30 во второй
1) х
2) 90-х
х-1/4х=90-х+1/4х
3/4х=90-3/4х
3/4х+3/4х=90
6/4х=90
х=90:6/4
х=90*4/6=60 в первой
90-60=30 во второй