Question

3x20=3x(10+_) what is the answer?

Answer 1

10 is the answer because 3×20=3×(10+10). 10+10 equals 20, so the answer matches 3×20.

Answer 2

The obvious answer to this would be 10.

The most simple way to do it would be taking out 3 x from each side of the equation and do 20 = 10 + _

Another way would be to actually solve it.

Let us put into the situation that the unknown variable would be y. The equation then would look like this.

3 x 20 = 3 x (10 + y)

Then solve

3 x 20 = 3 x (10 + y)
--------    ---------------
   3                  3
20 = 10 + y
20 - 10 = y
10 = y

10 would be the answer