earnings = $7 per hour
He needs at least $230 . This means he needs an amount greater than or equals to $230.
let
t = hour many hours he works
Therefore,
He needs to work approximately 33 hours or more to get at least $230 for his sterio. This means t is greater than or equals to approximately 33.
An exponent signifies repeated multiplication.
the factor x is repeated 3 times
Exponents can be added and subtracted to express the effects of multiplication and division.
The addition and subtraction of exponents works the same even when there are more denominator factors than numerator factors.
That is, a negative numerator exponent is the same as a positive denominator exponent and vice versa. You can move a factor with an exponent from denominator to numerator and change the sign of the exponent, and vice versa.
Your expression has 3 in the denominator with a negative exponent. It can be moved to the numerator and the exponent changed to positive: