Significant figures mean how many DECIMAL places you round to, not the digits before the decimal. In your case, 104.7197551 rounded to 3 significant figures would be 104.720
X will represent unknown 2x-4<3x treat the < sign as a = sign 2x-4=3x subtract 2x form both sides -4=x put the < sign back -4<x -4 is less than than x or x is greater than -4
