Answer:
x can be 3, -3, i, or -i.
Step-by-step explanation:
If you can't find the factoring by looking at this, simplify the equation.
let
x
2
=
y
to make things easier to see
Now we have
y
2
−
8
y
−
9
=
0
See it now?
We can factor into
(
y
−
9
)
(
y
+
1
)
Now substitute back in
x
2
for
y
.
(
x
2
−
9
)
(
x
2
+
1
)
Since
(
x
2
−
9
)
is a difference of two squares,
(
x
−
3
)
(
x
+
3
)
Now we have
(
x
−
3
)
(
x
+
3
)
(
x
2
+
1
)
x can be 3, -3 for the first two parts
x
2
+
1
=
0
can become
x
2
=
−
1
Taking the positive and negative root means
x
=
±
√
−
1
Thus
x
=
±
i
in addition to 3 and -3.
Answer:
x != -2, x^2 + 1, 1/5
Step-by-step explanation:
(a) It can be understood that nothing can divide 0
thus denominator cannot be 0 meaning x cannot be -2.
(-2 + 2) = 0
(b) y = sqrt(x-1)
inverse meaning we make x the subject
square both sides
y^2 = x - 1
y^2 + 1 = x
inverse = x^2 + 1
(c) composite function:
pass g(10) as domain of f
g(10) = 3, f(3) = 1/(5) = 1/5
Answer: the sample size should be 39
Step-by-step explanation:
The sample mean is the point estimate for the population mean. Confidence interval is written as
Sample mean ± margin of error
Margin of error = z × σ/√n
Where
σ = population standard Deviation
n = number of samples
z represents the z score corresponding to the confidence level
From the information given,
σ = 4 minutes
Margin of error = 75 seconds. Converting to minutes, it becomes 75/60 = 1.25 minutes
To determine the z score, we subtract the confidence level from 100% to get α
α = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
This is the area in each tail. Since we want the area in the middle, it becomes
1 - 0.025 = 0.975
The z score corresponding to the area on the z table is 1.96. Thus, confidence level of 95% is 1.96
Therefore,
1.25 = 1.96 × 4/√n
1.25/1.96 = 4/√n
0.6378 = 4/√n
√n = 4/0.6378 = 6.27
n = 6.27² = 39
Answer:
Step 4
part a: no answer yet still having trouble showing my work
part b:
-0.125(x-24)^2+50
-0.125(x-24)(x-24)+50
-0.125(x^2-24x-24x+576)+50
-0.125(x^2-48x+576)+50
-0.125x^2+6x-75+50
-0.125x^2+6x-22
a=-0.125
b=6
c=-22
part c: yes he went through
part d:
plug in roots (4,0) and (44,0)
if x is 4 and y is 0
0=-0.125(4)^2+6(4)-22
0=-2+24-22
0=-2+2
0=0
if x=44 and y=0
0=-0.125(44)^2+6(44)-22
0=-242+264-22
0=-242+242
0=0
