The answer for the question is -33
Answer:
189
Step-by-step explanation:
You can replace the values of x with 9 and the values of y with (-3).
7(2x-3y) = 7(2 × 9 - 3 × -3)
= 7(18 - -9)
= 7(18+9)
= 7 × 27
= 189
306 is the total cards sent by all the students in the class. Lets say x is the number of students in class, therefore each student needs to send x-1 cards (since they do not send themselves a card). So depending on your level of math, you could either take the complex way to solve it using quadratic equations, or just find the number that if multiplied by itself then subtracted, gives you 306.

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Complex way

So a = 1, b = -1, c=-306
using the quadratic equation:

Answer:
13 years old
Step-by-step explanation: 1 less than 9 is 8. you add five to 8 to get current age
Answer:
The answer is 8/1
Step-by-step explanation:
4/5÷1/10
4/5×10/1
=8/1