72+36x2+24x3+18x4+12x6+168
=72+72+72+72+72+168
=360+168
=528
`72 + 36 xx 2 + 24 xx 3 + 18 xx 4 + 12 xx 6 + 168`
`= 72 + 72 + 72 + 72 + 72 + 168`
`= 72xx5+168`
`= 360+168`
`=528`
` 72 + 36 . 2 + 24 . 3 + 18 . 4 + 12 . 6 + 168 `
` = 72 + 72 + 72 + 72 + 72 + 168 `
` = 72 . 5 + 168 `
` = 360 + 168 `
` = 528 `