Answer:
Step-by-step explanation:
Move 729 to the left side of the equation by subtracting it from both sides. x 3 − 729 = 0 Factor the left side of the equation. Rewrite 729 as 9
3
. x
3
−
9
3
=
0
. Since both terms are perfect cubes, factor using the difference of cubes formula, a
3
−
b
3
=
(
a
−
b
)
(
a
2+ab+b2). Where a
=x and b=9. (x−9)(x2+x⋅9+92)=0
. Simplify. Move 9 to the left of x
. (x−9)(x2+9x+92)=0. Raise 9 to the power of 2
. (x
−9
)(
x
2
+
9
x
+81
)=0
. Set x
−9 equal to 0 and solve for x. Set the factor equal to 0. x−
9=
0. Add 9 to both sides of the equation. x=9
. Set x2+
9
x
+
81 equal to 0 and solve for x
. Set the factor equal to 0
. x2+9x+81=0. Use the quadratic formula to find the solutions. −b±√b2−4(ac) 2a. Substitute the values a=1, b=9, and c=81 into the quadratic formula and solve for x. −9±√92−4⋅ (1⋅81
) 2⋅
1 Simplify. Simplify the numerator. Raise 9 to the power of 2. x=−9±√81−4⋅(1⋅81) 2⋅1. Multiply
81
by
1
.
x
=
−
9
±
√
81
−
4
⋅
81
2
⋅
1
Multiply
−
4
by
81
.
x
=
−
9
±
√
81
−
324
2
⋅
1
Subtract
324
from
81
.
x
=
−
9
±
√
−
243
2
⋅
1
Rewrite
−
243
as
−
1
(
243
)
.
x
=
−
9
±
√
−
1
⋅
243
2
⋅
1
Rewrite
√
−
1
(
243
)
as
√
−
1
⋅
√
243
.
x
=
−
9
±
√
−
1
⋅
√
243
2
⋅
1
Rewrite
√
−
1
as
i
.
x
=
−
9
±
i
⋅
√
243
2
⋅
1
Rewrite
243
as
9
2
⋅
3
.
Tap for fewer steps...
Factor
81
out of
243
.
x
=
−
9
±
i
⋅
√
81
(
3
)
2
⋅
1
Rewrite
81
as
9
2
.
x
=
−
9
±
i
⋅
√
9
2
⋅
3
2
⋅
1
Pull terms out from under the radical.
x
=
−
9
±
i
⋅
(
9
√
3
)
2
⋅
1
Move
9
to the left of
i
.
x
=
−
9
±
9
i
√
3
2
⋅
1
Multiply
2
by
1
.
x
=
−
9
±
9
i
√
3
2
Factor
−
1
out of
−
9
±
9
i
√
3
.
x
=
−
1
9
±
9
i
√
3
2
Multiply
−
1
by
−
1
.
x
=
1
−
9
±
9
i
√
3
2
Multiply
−
9
±
9
i
√
3
by
1
.
x
=
−
9
±
9
i
√
3
2
The final answer is the combination of both solutions.
x
=
−
9
−
9
i
√
3
2
,
−
9
+
9
i
√
3
2
The solution is the result of
x
−
9
=
0
and
x
2
+
9
x
+
81
=
0
.
x
=
9
,
−
9
−
9
i
√
3
2
,
−
9
+
i
√
3
2
Answer:
x = -3
Step-by-step explanation:
16x − 4 + 5x = -67
Combine like terms
21x -4 = -67
Add 4 to each side
21x-4+4 = -67+4
21x = -63
Divide each side by 21
21x/21 = -63/21
x = -3
Answer:
And we can find this probability using the complement rule and with excel or the normal standard table:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the weights of a population, and for this case we know the distribution for X is given by:
Where 
and 
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the complement rule and with excel or the normal standard table:
Answer:
Alright just simplify the expression So the exact form is
Exact form: 3/40 Hope this helps :)
Step-by-step explanation:
Answer:
and 
Step-by-step explanation:
Options
Required
Select the unit rates
Unit rate involve two items where the first item being measured can be any positive number, but the second item must be measured in units (i.e. 1)
For clarity:
If 
represents unit rate, then 
Having said that:
Only and satisfy the condition of unit rates; others are not because they have a denominator other than 1
