Question

Given the replacement set {0,1,2,3,4}, solve 6x-9=15

Answer 1

You can solve this two ways:
One is by substituting in the numbers until you get 15=15.

6(0)-9=15
0-9=15
-9=15

6(1)-9=15
6-9=15
-3=15

6(2)-9=15
12-9=15
3=15

6(3)-9=15
18-9=15
9=15

6(4)-9=15
24-9=15
15=15
Solution is x=4

or you can find the value of x
by first adding 9 to both sides to get x by itself

6x-9=15
6x=24

Then divide by 6
x=4