Can anyone explain this to me ? : )

Hey, personally I don't know but use photomath on your phone.

This is all about PEMDAS
Parenthesis, exponents, mult/div, add/sub, this is the order that you are supposed to solve in

A) 3 - 2(-10)            (first Multiplication) 
     3 + 20 = 23        (then add)

B) 3 + 4(6 - 4)         (first parenthesis)
    3 + 4(2)               (then multiply)
    3 + 8 = 11           (then add)

C) (2 - 5)² + 10         (parenthesis)
     (-3)² + 10             (exponent)
     9 + 10 = 19         (add)

D) 3 * 6 + 2 - 10       (multiply)
     18 + 2 - 10          (the order in which you sub or add doesn't matter, i                                               added first)
     20 - 10 = 10

E) 3 + 4 * 5 - 20          (multiply)
     3 + 20 - 20 = 0       (add/sub) 

A is the largest value

Hope this helps:)