Răspuns :
a×b= 2540
a×(b-100)= 1540
a×b-a×100= 1540
2540-100a= 1540
100a= 2540-1540
100a= 1000
a= 1000:100
a= 10
a×b= 2540
10b= 2540
b= 2540:10
b= 254
a×(b-100)= 1540
a×b-a×100= 1540
2540-100a= 1540
100a= 2540-1540
100a= 1000
a= 1000:100
a= 10
a×b= 2540
10b= 2540
b= 2540:10
b= 254