Answer:
D.) rational numbers are associative under subtraction
Step-by-step explanation:
rational numbers are closed under subtraction
↳ TRUE
zero is the identity for addition of rational numbers
↳ TRUE
subtraction is the inverse of the addition
↳ TRUE
rational numbers are associative under subtraction
↳ FALSE
3 4/5 because when you make the denominators equal by multiplying 1/4 by 5 on both sides and 4/5 by 4 and both sides you will get 5/20 and 16/20
For this case, the first thing we must do is define a variable.
We have then:
x: unknown number
We now write the equation that models the problem:
From here, we clear the value of x.
We multiply both sides of the equation by 2:
We subtract 30 on both sides of the equation:
Answer:
The value of the unknown number is given by:
Answer: 63 degrees.
Step-by-step explanation:
Angles in a triangle add up to 180 degrees.
Therefore: 54 + y + y = 180
So 54 + 2y = 180
So 2y = 126
Therefore y = 63 degrees.
Answer: 195
Step-by-step explanation:
Cost per student = $4
Total number who attended = n
The cost of the total of student who attended will be cost per student multiplied by the total number of students, that is
Total cos = 4n
Since, they are to pay $140 , for publicity, then the total cost becomes
T = 4n - 140
From the last statement
4n - 140 ≥ 640
4n ≥ 640 + 140
4n ≥780
n ≥ 780/4
n ≥ 195
That means at least 195 students must attend if the science club is to earn at least $ 640
