Bài 1 :
X x 405 = 86265 89658 : X = 293
X = 86265 : 405 X = 89658 : 293
X = 213 X = 306
\(x\times405=86265\)
\(x=86265:405\)
\(x=213\)
\(89658:x=293\)
\(x=89658:293\)
\(x=306\)
X x 402=86265
X=86365:405
X=213
Vậy X = 213
89658:X=293
X= 89658:293
X=306
Vậy X = 306