Answer:
The unknown number is 12.
Explanation:
Let the unknown number be 'x'
Given:
A number increased by 5 is equivalent to twice the same number decreased by 7.
So, 'x' increased by 5 means add 5 to 'x'. This gives
![x+5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/d9x9ggkicdatytjwtpdxc2831812xf0nqo.png)
Now,
is equivalent to twice of 'x' decreased by 7.
Twice of 'x' means 2 times of 'x' which is
![2x](https://img.qammunity.org/2020/formulas/mathematics/high-school/ehg1x3n3vnt1s4e4gae0epm9rgujr7wlmt.png)
'2x' decreased by 7 means subtract 7 from '2x'. This gives,
![2x-7](https://img.qammunity.org/2020/formulas/mathematics/high-school/o9zpioevdwvm60o1dbslh7xpp8ttg9d1qi.png)
Now,
and
are equivalent meaning they are equal. So,
![x+5=2x-7\\5+7=2x-x\\12=x\\x=12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/itclujavw9evz4t2ahva8nlcuorv9c9znq.png)
Therefore, the unknown number is 12.