Three liquids are given to you. one is hydrochloric acid; another is  sodium hydroxide and third is a sugar solution. how will you identify  them? you have only turmeric indicator. 

Wouldn't it be easier to use litmus paper?

Explanation: That way you could figure out the PH and know that the hydrochloric acid is acid and the alkaline is the sodium hydroxide. The sugar solution won't show either way.

you didn't list the options but im guessing it's resolving contradictions

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4