Answer:
9 + 4x = 101
Step-by-step explanation:
9 + 4x = 101 Equation
( +9 - 9 ) + 4x = ( 101 - 9 ) Subract 9 on both sides
4x = 92 Simplify
x = 23 Divide 4 on both sides
<em>23 people in art class</em>
Answer:
√
−
49
=
7
i
Explanation:
A square root of a number
n
is a number
x
such that
x
2
=
n
Note that if
x
is a Real number then
x
2
≥
0
.
So any square root of
−
49
is not a Real number.
In order to be able to take square roots of negative numbers, we need Complex numbers.
That's where the mysterious number
i
comes into play. This is called the imaginary unit and has the property:
i
2
=
−
1
So
i
is a square root of
−
1
. Note that
−
i
is also a square root of
−
1
, since:
(
−
i
)
2
=
(
−
1
⋅
i
)
2
=
(
−
1
)
2
⋅
i
2
=
1
⋅
(
−
1
)
=
−
1
Then we find:
(
7
i
)
2
=
7
2
⋅
i
2
=
49
⋅
(
−
1
)
=
−
49
So
7
i
is a square root of
−
49
. Note that
−
7
i
is also a square root of
−
49
.
What do we mean by the square root of
−
49
For positive values of
n
, the square root is usually taken to mean the principal square root
√
n
, which is the positive one.
For negative values of
n
, the square roots are both multiples of
i
, so neither positive nor negative, but we can define:
√
n
=
i
√
−
n
With this definition, the principal square root of
−
49
is:
√
−
49
=
i
√
49
=
7
i
Footnote
The question remains: Where does
i
come from?
It is possible to define Complex numbers formally, as pairs of Real numbers with rules for arithmetic like this:
(
a
,
b
)
+
(
c
,
d
)
=
(
a
+
c
,
b
+
d
)
(
a
,
b
)
⋅
(
c
,
d
)
=
(
a
c
−
b
d
,
a
b
+
c
d
)
These rules for addition and multiplication work as expected with commutativity, distributivity, etc.
Then Real numbers are just Complex numbers of the form
(
a
,
0
)
and we find:
(
0
,
1
)
⋅
(
0
,
1
)
=
(
−
1
,
0
)
That is
(
0
,
1
)
is a square root of
(
−
1
,
0
)
Then we can define
i
=
(
0
,
1
)
and:
(
a
,
b
)
=
a
(
1
,
0
)
+
b
(
0
,
1
)
=
a
+
b
i
Answer:
C
Step-by-step explanation:
Cause C met the rules of scientific notation which is:
- (First digit of the number) followed by (the decimal point) and then (all the rest of digits of the number) times (10 to an appropriate power)
This is the answer to your problem.
Answer:
The equation is;
y = 1/3x
Step-by-step explanation:
The equation of a linear model is given as;
y = mx + b
m is the slope while b is the y intercept
As we can see, the y intercept is the origin and that means b is zero
To get the value of m, the slope, we have to use the slope equation
We simply select any two points on the line
We have the points as (6,2) and (15,5)
The equation of the slope is:
m = (y2-y1)/(x2-x1)
(x1,y1) = (6,2)
(x2,y2) = (15,5)
m = (5-2)/(15-6) = 3/9 = 1/3
So the equation will be;
y = 1/3x