Answer:
Keegan need to mow 11 times to his neighbors lawn to have enough money to buy the skateboards.
Explanation:
Consider the provided information.
It is given that Keegan need $140 and Keegan saved $30. Keegan also charges $10 each time he completes the job writing.
Let x the number of times Keegan needs to mow his neighbors lawn to earn enough money.
Thus the required equation is;

Now solve the equation as shown below:




Hence, Keegan need to mow 11 times to his neighbors lawn to have enough money to buy the skateboards.