0.456=-0.3 (7n-31.2)

what is the variable?

Rewrite the equation as;

-0.3 (7n - 31.2) = 0.456

Divide each term by 0.3 and simplify;

-7n + 31.2 = 1.52

Move all terms not containing n to the right side of the equation;

-7n = - 29.68

Divide each term by - 7 and simplify;

n = 4.24