Hello Guys i was doing a Algebra SAT question.. and it was logical so i believe i got the right answer but in the future i don't want to get confuse so is there anyway to set an equation for this ?.

If 2x+2x+2x+2x=12 Then what is 2x-1=

I got that X is 2 because 2.2=4,2.2=4 2.2=4 =12 so 2.2-1=3

But i really don't know what would i ahve done if it was a bigger number..