(700•a+200)-600=1000 (7200-а•200)+2000=3400 (y: 4-35)•120=3000 (50•y+160)-60=500

1)(700*a+200)-600=1000
700a-400-1000=0
700a-1400=0
700a=1400
a=2

2)(7200-а*200)+2000=3400
9200-200a-3400=0
5800-200a=0
-200a=-5800
200a=5800
a=29

3)((y/4)-35)*120=3000
30y-4200-3000=0
30y-7200=0
30y=7200
y=240

4)(50*y+160)-60=500
50y+100-500=0
50y-400=0
50y=400
y=8

(700*a+200)-600=1000
700a+200-600=1000
700a-400=1000
700a=1000+400
700a=1400
a=2

(7200-a*200)+2000=3400
(7200-200a)+2000=3400
7200-200a+2000=3400
9200-200a=3400
-200a=3400-9200
-200a=-5800
a=29

(y:4-35)*120=3000
(y/4-35)*120=3000
30y-4200=3000
30y=3000+4200
30y=7200
y=240

(50*y+160)-60=500
50y+160-60=500
50y+100=500
50y=500-100
50y=400
y=8