How do i solve for x (ax+bx) / 3=c in terms of a and b and c

Already in terms of c x (ax+bx) / 3=c

(ax^2 + bx^2) / 3=c. Multiply parentheses by x

ax^2 + bx^2=3c. Multiply each side by 3

ax+bx=√3c. Take the square root of both sides

x (a+b) = √3c

a+b=√3c/x

a=√3c/x - b or b=√3c/x - a