Answer:
x≥-8
Explanation:
Because we don't know the first number mentioned, we can name it as x
Since the problem starts off with "twice a number" so we mark it as 2x and then it states to take the difference of that number and 9. So the new problem we have is 2x-9=?. Now, the answer that we have is at least -25, so the answer is no longer an equal sign, but a greater-than or equal-to sign. Making our new equation 2x-9≥-25. Now we can act as if its a normal equation, adding 9 to both sides making it 2x≥-16, divide both sides by 2 to get x≥-8.
An extra step to ensure our answer is more than or equal to -8 is by plugging in -8 AND another number that is more than -8. 2(-8)-9=? which we would find that ? is -25. A number that is greater than -8 could be -1, which we would test by doing 2(-1)-9=?. ? would be equal to -11 so we know that our final answer of x≥-8 is correct.