Solving for x in equation for chem

Question

In the answers to a chem problem is just gives this equation: (34.969) (x) + (36.966) (1 - x) = 35.453, and says solve for x. But I have no clue how to solve for x....

Answer 1

$$ax+b(1-x)=c,$$ so $$(a-b)x+b=c,$$ so $$(a-b)x=c-b,$$ so $$x=\frac{c-b}{a-b}.$$ provided $a\neq b$.