How do you know you found a solution? For example is point (-2,4) a solution to the above equation?

Any greatly appreciated! you in advance. jody bought 20 shares of amazon at the close price of $121.00. she bought 20 more shares a year later at the price of $127.00. two years later she's sold all of her shares at the price of $133.00. her broker charges $50 for each transaction. after all of these transactions how much money did jody make? a.$65.00b.$5288.00c.$210.00d.$310.00

Empty box + box + empty box fill in the box is equal to 30 how

The sum of two numbers is 12 and their difference is 18 what are the two numbers