How would you solve 3x+9y=6

First, you wanna subtract 9 from both sides which gives you - 3. Next, you'll have to divide both sides by 3 but first you gotta cancel out 3x : 3 and divide - 3 by 3 which then gives you the answer to x which is - 1.

3x + 9 = 6

3x + 9 - 9 = 6 - 9

3x = - 3

3x : 3 = - 3 : 3

x = - 1