Solve for x. 2x + 6 - 6x = 30

A. - 6

B. - 3

C. 3

D. 6

So,

2x + 6 - 6x = 30

Collect Like Terms.

-4x + 6 = 30

Subtract 6 from both sides.

-4x = 24

Divide both sides by - 4.

x = - 6

Check.

2x + 6 - 6x = 30

2 (-6) + 6 - 6 (-6) = 30

-12 + 6 + 36 = 30

-6 + 36 = 30

30 = 30 This checks.

S = {-6}

That is option A.