Answer:
-18
Step-by-step explanation:
-18 
brainlest please
 
        
             
        
        
        
Numbers whose only factors are 1 and itself is known as prime numbers , numbers whose factors besides 1 and itself are composite numbers, we can use the sieve of Eratosthenes to determine whether the number is prime or composite.
Given a paragraph in which there are blanks:
A _____ is a number whose only factors are 1 and itself. If a number has  factors besides 1 and itself, it is called a _____. You can use divisibility rules or _______ to help you determine whether a number is prime or composite.
We are required to fill the blank with appropriate options.
We have to fill "prime numbers" in the first blank.
We have to fill "composite numbers" in the second blank.
We have to fill "the sieve of Eratosthenes" in the third blank.
Hence numbers whose only factors are 1 and itself is known as prime numbers , numbers whose factors besides 1 and itself are composite numbers, we can use the sieve of Eratosthenes to determine whether the number is prime or composite.
Learn more about prime numbers at brainly.com/question/145452
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Answer:
0.000025
Step-by-step explanation:
PEMDAS (Exponets first.)
10^5 = 100,000
10^10 = 10,000,000,000
rewrite
2.5 x 100,000 divided by 1.0 x 10,000,000,000
PEMDAS (multiplication next.)
2.5 x (10^5) = 250,000
1.0 x (10^10) = 10,000,000,000
rewrite.
250,000 divided by 10,000,000,000 = 0.000025
0.000025
 
        
             
        
        
        
Answer:
x = 0, y = 7
Step-by-step explanation:
Solving a system of equations using substitution requires one side to be equal to a variable present in the equation, in this case x or y. We should simplify the equation using elimination before substituting to reduce the chance of error.
In order to use the elimination method, you have to create variables that have the same coefficient—then you can eliminate them. These equations arew already aligned for us.
                   3x - 10y=-70
              -<u>   4x +9y = 63</u>
                   -x + y = 7
Now, for substitution, the equation must be set to a variable.
                   -x + y = 7
                   y = x + 7
Next, plug the equation in where applicable in another equation.
                   4x +9(x + 7) = 63
                   4x + 9x + 63 = 63
                   13x = 0
                   x = 0
The final step of substitution is to plug the known variable into an equation to find the other variable.
                   3(0) - 10y=-70
                   0 - 10y = -70
                   10y = 70
                   y = 7
I guarantee you this answer is correct, I worked it out using other methods and graphing prior to submitting this answer.