goi 2 so can tim la a va b thi theo de bai ta se co a+b= 12 x 5 +5 = 65
a-b = 2 x 6 +3 = 15
Cong thuc tim 2 so khi biet tong va hieu cua chung la So lon = (tong + hieu): 2 So be = (tong-hieu):2
ap dung cong thuc do ta duoc a=(65+15):2=40 b=(65-15):2=25
Vay dap an la A . Chuc ban hoc tot !
Dáp án A nha bạn!