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Softa [21]
3 years ago
10

What are the roots of this equation?

Mathematics
1 answer:
Katyanochek1 [597]3 years ago
4 0

Answer:

x = 2 ± (i)√5  (Answer b)

Step-by-step explanation:

x²-4x+9=0 can be solved in a variety of ways; the first two that come to mind that are also appropriate are (1) completing the square and (2) using the quadratic formula.

Completing the square is fast here:

Rewrite x²-4x+9=0 as   x²-4x                    +9=0

Identify the coefficient of the x term:  it is -4

Take half of that, obtaining -2

Square this result, obtaining 4

Add 4 to   x²-4x                    +9=0, in the blank space in the middle, and then subtract 4:      x²-4x +4          -4         +9=0

Rewrite           x²-4x +4 as the square of a binomial:

                          (x - 2)² - 4 + 9  = 0  →    (x - 2)²  = -5

Take the square root of both sides:       x - 2  = ±√(-5)  =  ± (i)√5

Then x = 2 ± (i)√5

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If a recipe for 24 cookies needs 2 cups of flour, how many cups would we need to make 42 cookies?
TEA [102]

Answer:

3 1/2 cups

Step-by-step explanation:

24=2

42=x

24x=84

/24   /24

3.5

6 0
2 years ago
Find the measure of each missing angle.
nadya68 [22]

Answer:

Step-by-step explanation:

Angle sum property of triangle: Sum of all the angles of a triangle is 180

Alternate interior angles: When two parallel lines are intersected by a transversal, the pair of angles on the inner side of  each of these lines but on the opposite side of the transversal are called  alternate interior angles

In ΔABC,

  ∠1 + 90 + 38 = 180    {angle sum property of triangle}

         ∠1 + 128 =  180

               ∠1     = 180 - 128

            \sf \boxed{\bf  \angle 1     = 52^ \°}

AB // CD and AC is transversal.

 \sf \boxed{\bf  \angle 3 = 38^\circ}   {Alternate interior angles are equal}

In ΔACD,

      ∠2 + ∠3 + 63 = 180 {angle sum property of triangle}

       ∠2 + 38 +63  = 180

               ∠2  + 101 =180

                         ∠2 = 180 - 101

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5 0
2 years ago
∆ABC and ∆FDE are congruent by the criterion. (Use the three-letter abbreviation without spaces.)
Anastasy [175]

Answer:

x = 11, y = 8

Step-by-step explanation:

ΔABC and ΔFDE are congruent by the postulate SSS

Equate the congruent sides in the 2 triangles

BC = ED, that is

x + 3 = 14 ( subtract 3 from both sides )

x = 11

-------------------------------------

DF = AB, that is

x - y = 3 ← substitute x = 11

11 - y = 3 ( subtract 11 from both sides )

- y = 3 - 11 = - 8 ( multiply both sides by - 1 )

y = 8

6 0
3 years ago
Read 2 more answers
Keenan will run 2.5 miles from his house to Jared’s house. He plans to hang out for 45 minutes before walking home. If he can ru
jenyasd209 [6]

Answer:

Kennan will be from home approximately an hour and 48 minutes.

Step-by-step explanation:

We must know that total time (t_{T}) that Keenan will be from home is the sum of run (t_{R}), hang out (t_{H}) and walk times (t_{W}), measured in hours:

t_{T} = t_{R}+t_{H}+t_{W}

If Keenan runs and walks at constant speed, then equation above can be expanded:

t_{T} = \frac{x_{R}}{v_{R}}+t_{H}+ \frac{x_{W}}{v_{W}}

Where:

x_{R}, x_{W} - Run and walk distances, measured in miles.

v_{R}, v_{W} - Run and walk speeds, measured in miles per hour.

Given that x_{R}=x_{W} = 2.5\,mi, v_{R} = 6\,\frac{mi}{h}, v_{W} = 4\,\frac{mi}{h} and t_{H} = 0.75\,h, the total time is:

t_{T} = \frac{2.5\,mi}{6\,\frac{mi}{h} } + 0.75\,h+\frac{2.5\,mi}{4\,\frac{mi}{h} }

t_{T} = 1.792\,h (1\,h\,48\,m)

Kennan will be from home approximately an hour and 48 minutes.

7 0
3 years ago
Transversal relations
Shalnov [3]

Answer:

The answer is 75

Step-by-step explanation:

By way of parallelism

x + 15 = 90 \\ x = 75

7 0
2 years ago
Read 2 more answers
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