He sum of negative eighteen and a number is eleven. what is the number? which equation could be used to solve the problem?

Pls! does anybody know a shortcut for answering these types of questions in the future?

Merrida uses a pattern in the multiplication table below to find ratios that are equivalent to 7: 9. if merrida multiplies the first term, 7, by a factor of 6, what should she do to find the other term for the equivalent ratio? multiply 9 by 1. multiply 9 by 6. multiply 9 by 7. multiply 9 by 9.

From the beginning of the day the temperature rose 15 degrees so that by 4 pm it was 87 degrees. what was the temperature at the start of the day