Can someone help me with this math problem. The slope is 15 and the y-intercept is 10

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Aline passes through the point (–7, 5) and has a slope of 1/2 which is another point that the line passes through?

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 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?