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2 years ago

What are the roots of this equation?

Mathematics

1 answer:

Katyanochek1 [597]2 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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Help me please please

harina [27]

Answer:

$EH = \sqrt{HG^2+EG^2} = \sqrt{4^2+6^2} = \sqrt{16+36} = \sqrt{52} = 2\sqrt{13}$

EG² = GH*GF
EG² = 4*12
EG² = 48
EG = √48 = 4√3

3 0

3 years ago

When Mrs. Stewart makes pie dough, she uses 2/3 cup of shortening for every 2 1/2 cups of flour which proportion could be used t

n200080 [17]

Answer:

She will use the ratio shortening to flour as 4 : 15

Step-by-step explanation:

When Mrs. Stewart makes pie dough, she uses $\dfrac{2}{3}$ cups of shortening for every $2\dfrac{1}{2} = \dfrac{5}{2}$ cups of flour.

So, for each $\dfrac{2}{3}$ cup of shortening she uses $\dfrac{5}{2}$ cups of flour.

Then, the ratio of shortening to flour in the mixture of pie dough will be

$\dfrac{\dfrac{2}{3} }{\dfrac{5}{2} } = \dfrac{4}{15}$ i.e. 4 : 15.

Therefore, she will use the ratio shortening to flour as 4 : 15 to find the amount of flour she needs when she uses 5 cups of shortening. (Answer)

3 0

3 years ago

The price of a computer was decreased by 30% to £147. What was the price before the decrease?

Sunny_sXe [5.5K]

Answer:

£210

Step-by-step explanation:

A decrease of 30% represents 70% of the original cost.

100% represents the original cost

Divide the price by 70 to find 1% then multiply by 100 for original cost

original cost = $\frac{147}{70}$ × 100 = 2.1 × 100 = £210

4 0

3 years ago

Read 2 more answers

Using the slope formula, find the slope of the line through the given points.

BabaBlast [244]

Answer:

-2

Step-by-step explanation:

Slope = (4-8) / (9-7) = -4/2 = -2

5 0

2 years ago

In a video game, a bird is flung on a sling shot and follows a parabolic path. The path of the bird can be modeled by the equati

umka21 [38]

9514 1404 393

Answer:

3.61 seconds

Step-by-step explanation:

The bird starts 50 feet in the air, so will come down to a height of 40 feet after 3.61 seconds.

We want to solve h = 40.

40 = -16t^2 +55t +50

16t^2 -55t -10 = 0

t = (55 +√(55^2 -4(16)(-10)))/(2(16)) = (55 + √3665)/32 ≈ 3.61060

The bird will be 40 ft above the ground the first time after about 3.61 seconds.

8 0

3 years ago