Move the 8 over
-x=3x-8
Move the 3x over
-x-3x=8
-4x=8
Divide by -4
x=-2
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:
Maximum
Step-by-step explanation:
The green dot repesents the max height of the parabola.
Helpful tip:
If the graph opens up then the vertex is a min
If the graph opens down then the vertex is a max
Answer:
Step-by-step explanation:
Given that the time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes.
P(completing exam before 1 hour)
= P(less than an hour) = P(X<60)
=P(Z<
)
=0.5-0.34=0.16
i.e. 16% of students completed the standardized exam.
Round each coin weight to the nearest gram first, penny 3g, nickel 5g, dime 2g, quarter 6g, half dollar 11g. Now add those numbers together as he has one of each coin 3+5+2+6+11=27 grams
