I assume that the "d2" was a typo as a problem such as this with 2 variables would require a system of equations.
I also assume that the ? is a typo and will replace it with 0, however you can repeat my steps with whatever it actually it.
I assume that the correct form is 2 + 3a + 6 + a = 0
2 + 3a + 6 + a = 0
Combine like terms
8 + 3a + a = 0
8 + 4a = 0
move 8 to other side
4a = -8
a= -8/4
a = -2*
plug this value of a into the original equation
2 + 3(-2) + 6 + (-2) = 0
The statement is true!
* This probably isn't your answer! Repeat my steps with whatever the value of "?" is.
