Answer :

To get the answer we have to solve eq.
7(5+9)=7x+7*9
7*5+7*9=7x+63
35+63=7x+63        /-63 
35=7x           /:7
5=x
The correct answer is B.

B.
X=5

7(5+9)=7•x+7•9
(7•5)+(7•9)=7x+63
35+63=7x+63

Subtract 63 from both sides and you will be left with
35=7x
Divide each side by 7 (you pretty much just divide 35 by 7)

And x=5