2 、( 1+20%)X =(X- 10)/2

(1+20%) * 35 = 42 is not equal to 25, so it is not.

Solve (1+20%)X =(X- 10)*2 to get X=25, that is, class B planted 25 trees, so class A planted (x-10) * 2 = (25-10).

Don't worry, it's absolutely true. I have also done this topic.