9x^2 + 18x + 9 = 5
9(x^2 + 2x +1) - 5 = 0
x^2 + 2x - 4 = 0
Then use the quadratic formula.
Answer:
y= -3
Step-by-step explanation:
(-7/2)y =21/2
Divide both sides by (-7/2) = Multiply by (-2/7)
On the left side ,after cancellation you have only y
On the right side you multiply 21/2 by (-2/7)
y= (21*-2) / 2*7
y=(-42)/14
y=(-21)/7
y=- 3
check:
-(7/2) of- 3 is 10.5 21/2=10.5
X = 3
y = -1
get the x or y by itself first (second eq. is easier)
So, x + 2y = 1
-2y -2y
Now we get:
x = -2y +1 Plug it into the other equation.
2x + 3y = 3
2(-2y +1) + 3y = 3
-4y + 2 + 3y = 3
-1y +2 = 3
+1y -3 -3 +1 y
y = -1 (plug into either eq to get x)
<span>x + 2y = 1
</span>x+2(-1) = 1
x-2=1
+2 +2
x = 3
4:3
x:39
We need to find what 3 was multiplied by to get 39:
39/3 = 13.
Now multiply 4 by this number
4*13 = 52
Hope this helped!
Answer:
To use a paired t-test
Step-by-step explanation:
t-tests are essentially tests carried out to compare two different groups to check if there is a major difference in their performances or results which may be related in certain characteristics.
A paired (correlated) t-test is used when there are matched pair of similar units or instances of repeated measurements.
In this case, Mary has to use a paired t-test because the samples (students) have high similarity in characteristics. The students in question has to be from the same class to test her hypothesis (similar characteristics).
