Answer:
life does suck and I've been just having breakdownnnnns
Given
We have to set the restraint
because a square root is non-negative, and thus it can't equal a negative number. With this in mind, we can square both sides:
The solutions to this equation are 7 and -2. Recalling that we can only accept solutions greater than or equal to -1, 7 is a feasible solution, while -2 is extraneous.
Similarly, we have
So, we have to impose
Squaring both sides, we have
The solutions to this equation are 5 and 10. Since we only accept solutions greater than or equal to 7, 10 is a feasible solution, while 5 is extraneous.
5n - 10 is the way to write the expression you wrote in English above.
It does not mean much until we set it equal to something.
For example:
The difference of five times a number n and 10 is 25.
Now
5n - 10 = 25
by subtracting 10 from each side we get 5n=35 and then if we divide both sides by 5, we get n=7.