a. 91056 = 9x510x6 = 3x$3$x$5$$5$x2x$3$x2

= 34

b. 625 :  2120 = 6x2025x21 = 2x$3$x4x$5$5x$5$x$3$x7

= 835

c. 407145 = 40x147x5 = 8x$5$x2x$7$$5$x$7$

= 161 = 16

d.  1713 : 5126 = 17x2613x51 = $17$x$13$x2$13$x3x$17$

= 23