If you mean to put it into y=mx+b, then simply input m and b into that formula.
So it would be y=1/2x-4
First you bring the x to one side so u subtract 4x from 7x and you get the new equation as -9=3x+12 then you just solve and you get x is equal to -7
The answer is no. because is you substitute the value 3 in for x into the equation and solve you get,
4(3)+3=18 which says 12+3=18 15=18 and that is an untrue statement.
Hope this helps explain the concept so you understand! Any questions feel free to ask! Please rate if I helped you! thank you so much!!
7/10 is bigger because it is more than half