Answer:
Step-by-step explanation:
When using the substitution method we use the fact that if two expressions y and x are of equal value x=y, then x may replace y or vice versa in another expression without changing the value of the expression.
Solve the systems of equations using the substitution method
{y=2x+4
{y=3x+2
We substitute the y in the top equation with the expression for the second equation:
2x+4 = 3x+2
4−2 = 3x−2
2=== = x
To determine the y-value, we may proceed by inserting our x-value in any of the equations. We select the first equation:
y= 2x + 4
We plug in x=2 and get
y= 2⋅2+4 = 8
The elimination method requires us to add or subtract the equations in order to eliminate either x or y, often one may not proceed with the addition directly without first multiplying either the first or second equation by some value.
Example:
2x−2y = 8
x+y = 1
We now wish to add the two equations but it will not result in either x or y being eliminated. Therefore we must multiply the second equation by 2 on both sides and get:
2x−2y = 8
2x+2y = 2
Now we attempt to add our system of equations. We commence with the x-terms on the left, and the y-terms thereafter and finally with the numbers on the right side:
(2x+2x) + (−2y+2y) = 8+2
The y-terms have now been eliminated and we now have an equation with only one variable:
4x = 10
x= 10/4 =2.5
Thereafter, in order to determine the y-value we insert x=2.5 in one of the equations. We select the first:
2⋅2.5−2y = 8
5−8 = 2y
−3 =2y
−3/2 =y
y =-1.5
Answer:
The mean.
Step-by-step explanation:
The mean is not robust.
The presence of an outlier greatly affects the value of a mean.
An example will illustrate this.
Find the mean of the numbers 2 3 5 6 34.
34 is an outlier. The mean = (2+3+5+6+34) / 5 = 10.
Now if we replace the outlier with a number closer to the others:
Say we have 2 3 5 6 8 :
The mean = (2+3+5+6+8) / 5 = 4.8 which is a much truer measure of centrality than 10.
Answer: (2x+3)(x+3)
Step-by-step explanation:
Looking at this, you know that it must look something like
(? +3)(?+3) , because they must multiply to 9. The ?s must multiply to 2x^2, the most plausible values being 2x and x, ending us up with (2x+3)(x+3)
Answer:
Step-by-step explanation:
4^(4-7+1) = 4^-2
7/9 of his trees are oak trees
