Question

Which of the following equalities are valid? Choose all that apply.

(3^2+4)-2=11
(3^2+4-2=5
2*(3^2-1)=16
2*(3^2-11)=35

Answer 1

Remember that an equation is valid if it has the same value in both sides. Lets evaluate each one of the qualities separately to check their validity:
1.
`(3^2+4)-2=11`

`(9+4)-2=11`

`13-2=11`

`11=11`
This one is valid.

2.
`(3^2+4)-2=5`

`(9+4)-2=5`

`13-2=5`

`11=5`
This one is not valid.

3.
`2(3^2-1)=16`

`2(9-1)=16`

`2(8)=16`

`16=16`
This one is valid.

4.
`2(3^2-11)=35`

`2(9-11)=35`

`2(-2)=35`

`-4=35`
This one is not valid.

We can conclude that the valid qualities are (3^2+4)-2=11 and 2*(3^2-1)=16