Please help. not tryna seem needy-

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Which must be true in order for the relationship △zyv ~ △xwv to be correct? zy ∥ wx ∠z ≅ ∠y and ∠w ≅ ∠x zv ≅ vy and wv ≅ vx ∠z ≅ ∠x and ∠w ≅ ∠y

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.