Answer :

74 because 3x equal 17+10. so x equals 9 and plug it in to the equation got 74
[tex]3x-10=17\ \ \ \ /+10\\\\3x-10+10=17+10\\\\3x=27\ \ \ \ /:3\\\\3x:3=27:3\\\\x=9\\\\\\\\6x+20=6\cdot9+20=54+20=74[/tex]



[tex]3x-10=17\ \ \ /\cdot2\\\\2\cdot3x-2\cdot10=2\cdot17\\\\6x-20=34\ \ \ \ /+40\\\\6x-20+40=34+40\\\\6x+20=74[/tex]