45/3=15 45-15=30 30/5=6 3x6=18 30-18=12 the answer is 12
Answer:

Step-by-step explanation:
In order to find what score Alex must earn to have an average of 86 on all his tests, we need to first note what the formula to find the average of a data set is.

What the formula means is that we have to add up all the values then divide by the total number of values.
Let's represent our unknown number as
.
(since we want AT LEAST an 86).
Let's solve this inequality for x.
So, Alex must score at least an 87% on his next quiz to have an average of 86%.
Hope this helped!
Answer:
6
Step-by-step explanation:
3x+6+5x+10=64
3x+5x+6+10=64
8x+16=64
8x=64-16
8x=48
divide both sides by 8
x=6
Answer:
1 second
Step-by-step explanation:


A good place to start is to set
to y. That would mean we are looking for
to be an integer. Clearly,
, because if y were greater the part under the radical would be a negative, making the radical an imaginary number, not an integer. Also note that since
is a radical, it only outputs values from
, which means y is on the closed interval:
.
With that, we don't really have to consider y anymore, since we know the interval that
is on.
Now, we don't even have to find the x values. Note that only 11 perfect squares lie on the interval
, which means there are at most 11 numbers that x can be which make the radical an integer. All of the perfect squares are easily constructed. We can say that if k is an arbitrary integer between 0 and 11 then:

Which is strictly positive so we know for sure that all 11 numbers on the closed interval will yield a valid x that makes the radical an integer.