Math7
posted by Miley .
Yuki made cookies on Monday. Some friends came over and ate half the cookies on Tuesday. On wednesday,Yuki ate three cookies, and on Thursday, she took two cookies to school. By Friday, Yuki had seven cookies left. How many did she bake on Monday?
Please i need help

x = number of cookies
x  (1/2 x + 3 + 2) = 7
x  (1/2 x + 5) = 7
2/2 x  1/2 x  5 = 7
1/2 x  5 = 7
1/2 x = 12
multiply both side by 2
x = 24 
Thank you!
I did one exercise and could you please check it
The temperature at 2:00 P.M was 19C. By midnight, it was 3C
What is the difference in the temperatures?
_____________=________
I thing the answer is:
(+19)(+22)=3
Correct? 
Correct?

How can a difference between 19 and  3 be only 3 degrees?

From 19C to 3C is 22 degrees difference

Thank you!!