We have to use the Distributive Property in this equation.
By the Distributive Property,

becomes

Now we need to isolate x. Remember PEMDAS?


Simplify the right side.

Kx+9=7
Kx=-2 (subtract 9 from both sides)
X=-2/k (divide k from both sides.
A fraction that is a multiple of 4/5 is 8/10, because you multiply both numbers by two.
We collect like terms
8x - 3x = 3 + 5 + 9
This is bcos if a (-) sign crosses the equals sign it becomes a (+), and if a (+) sign crosses the equals sign it becomes (-)
We the have
5x = 17
Divide both sides by 5
x = 17/5
x = 3.4