đặt A= 3.2410=3.(8.3)10=\(\frac{3}{2}\).2.230.(\(\frac{3}{2}\))10 . 210 = \(\left(\frac{3}{2}\right)^{11}.2^{41}\)
đặt B=230+330 + 430 =230 +\(\left(\frac{3}{2}\right)^{30}.2^{30}+2^{60}\)
A-B= \(\frac{3}{2}^{11}.2^{41}-2^{30}-2^{30}.\left(\frac{3}{2}\right)^{30}-2^{60}\)
=\(2^{30}\left(2^{11}.\left(\frac{3}{2}\right)^{11}-1-\left(\frac{3}{2}\right)^{30}-2^{30}\right)\)
=\(2^{30}\left(3^{11}-1-\left(\frac{3}{2}\right)^{30}-2^{30}\right)A\)
nhớ ****