1 a. If x=6a+3 and a is 4 what is x? b. Make a the subject of the formula.

1a. a=4 Substitute the number into the equation x= (6 x 4) + 3= 24 + 3= 27
b. We need to isolate a So minus three from both sides to start with (what you do to one side you must do to the other, otherwise you are changing the equation)x-3=6aTo move the 6 divide both sides by 6, because 6/6 is 1 so just leaves a (x-3)/6=a