Câu trả lời:
A−(615+315)×49=59A-(615+315)×49=59
A−915×49=59A-915×49=59
A−415=59A-415=59
A=59+415A=59+415
A=3745A=3745
______________________________
(B+78)×3614=154(B+78)×3614=154
B+78=154:3614B+78=154:3614
B+78=3524B+78=3524
B=3524−78B=3524-78
B=712