first

(65+X)/( 100-X)= 16/ 17； So the two sides of the equation multiply each other. Namely:17 * (65+x) =16 * (100-x), multiplied by the number:1105+17x =/kloc-. The two-side shift term of the equation is 33x =1600-105, that is, 33X=495, and the solution is X= 15.

second

If the number of red balls is X, the number of yellow balls is X+30. According to the meaning, it can be listed as: x+1=1/3 * (x+30+1). Continue to move the term to solve the equation: 3x+3=x+3 1, and continue.