Question

x : 5 =1400-900

x-30=1000-200

Answer 1

х:5=1400-900
х:5=500
х=500*5
х=2500
____________
2500:5=500
500=500

x-30=1000-200
х-30=800
х=800+30
х=830
____________
830-30=800
800=800