0.35/((2/3)x) = 0.45/(x−10)

X=70 because you have to convert the decimals to fractions so that the .35 equals 7/20 and .45 equals 9/20 then simplify the complex fractions on each side so 7/20 over 2X/3 equals 21/40X and the 9/20 over the X-10 equals 9/20(X-10), then cross multiply to get 420 (X-10)= 320X, next you would distribute the 420 through the parenthesis to get 420X-4200=360X, then add 4200 to both sides so 420X on its own then add 360X on both sides so both X's are on the same side then combine like terms and get 60X on the left, then divide both sides by 60 so X is on its own so X=70