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3 years ago

Find the zeros of y= x2 - 4x - 9 by completing the square.

Mathematics

1 answer:

ExtremeBDS [4]3 years ago

5 0

Answer:

Step-by-step explanation:

To find the zeros equate y to zero, that is

x² - 4x - 9 = 0 ( add 9 to both sides )

x² - 4x = 9

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(- 2)x + 4 = 9 + 4

(x - 2)² = 13 ( take the square root of both sides )

x - 2 = ± $\sqrt{13}$ ( add 2 to both sides )

x = 2 ± $\sqrt{13}$ → A

You might be interested in

Freddie gets paid £1500 per month he spends 20% on rent the rest is spent on food, travel and socialising in the ratio 2:3:1 res

ki77a [65]

Answer:

THIS IS THE ANSWER

Step-by-step explanation:

20% of 1500 = 300

2+3+1=6

300÷6=50

food=50×2=100

Travel=50×3=150

socialising=50×1=50

6 0

3 years ago

Don't have to do all of them just tell me the ones you do.

Alik [6]

See explanations below.

Step-by-step explanation:

12. If H(x) represent the percent of U.S households with internet use in x years after 1980 then;

a) H(23)=55 means the number of U.S households with internet use in 23 years after 1980 is 55

b)H(4)=k

so if in 23 years H, is 55, find in 1 year

In 1 year H= 55/23=k

c)H(27) ≥ 61 means in 27 years the number of U.S households with Internet use will be greater or equal to 61 households. If you check the results, in 27 years, H is 55/23 * 27 =64.5 ≅65 households which is at most 61 households.

d) H(17) + H(21)=H(29) means the sum of households with internet use in 17 years and 21 years after 1980 equal the number of households with internet use in 29 years.Checking the results;

H(17) = 55/23 *17 =40.65

H(21)=55/23 *21=50.22

H(17)+H(21)=40.65+50.22=90.87≅91 households

H(29)=55/23 * 29 = 69.34≅69 which is False

13.

h(x)=-7x ; h(x)=63 ⇒replacing x in the second function with -7x

-7x=63

x=63/-7

x=-9

14.

t(x)=3x ; t(x)=23

3x=23

x=23/3 = 7.67

14.

m(x) =4x +15 ; m(x)=7

4x+15=7

4x=7-15 -----------collecting like terms

4x=-7

x=-7/4

15.

k(x)=6x-12 ; k(x) =18

6x-12=18

6x=18+12-------collecting like terms

6x=30

x=30/6

x=5

16. q(x) =1/2x -3 , q (x) =-4

1/2 x-3 =-4------------multiply each term by 2

x-6= -8 ----------------collect like terms

x= -8+6

x= -2

17.

j(x)= -4/5 x + 7 ; j(x)= -5

-4/5 x +7 = -5 ---------multiply each term by 5

-4x+35= -25

-4x=-25-35

-4x=-60

4x=60

x=60/4

x= 15

Learn More

Functions ; brainly.com/question/2316114

Keywords : Functions

#Learnwithbrainly

3 0

3 years ago

WILL MARK YOU BRAINLIEST

Naddik [55]

I think x = 78
because 21/14 = 1.5
so x = 1.5*52
x = 78

5 0

3 years ago

May someone please help me out with this problem? May you also explain it?

gavmur [86]

Answer:

Step-by-step explanation:

Given function is,

f(x) = $\sqrt{x}$

If the given function is vertically stretched by a scale factor of $\frac{3}{2}$ Or 1.5,

Transformed function will be,

h(x) = $\frac{3}{2}[f(x)]$

h(x) = $\frac{3}{2}(\sqrt{x})$

Further function 'h' is shifted 1 units upwards,

g(x) = h(x) + 1

g(x) = $\frac{3}{2}(\sqrt{x} )+1$

Domain of the function → x ≥ 0 Or [0, ∞)

Range of the function → y ≥ 1 Or [1, ∞)

Transformations done → Parent function f(x) is vertically stretched by a scale factor of $\frac{3}{2}$ then shifted 1 unit upward.

3 0

3 years ago

Share £880 into the ratio of 3:1

Shkiper50 [21]

Answer:

1/880

Step-by-step explanation:

4 0

3 years ago