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3 years ago

Find the value of k for x^2 - 2kx+7k -12=0 so that they have two equal roots

Mathematics

1 answer:

Alisiya [41]3 years ago

5 0

Step-by-step explanation:

x^2 -2kx +7k -12 = 0

two equal roots -->Δ = b^2 -4ac = 4k^2 - 4(7k-12)=0 = 4(k^2 - 7k +12)=4(k-4)(k-3)=0

so k =3 and k =4

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Please solve all questions

fredd [130]

Answer:

1)x=-6,y=1 2)a=0,b=-8 3)j=8,k=1 4)m=3,n=-6

Step-by-step explanation:

1)x-4y=-10,2x+y=-11

x-4y=-10

x=4y-10

2\left(4y-10\right)+y=-11

8y-20+y=-11

9y-20=-11

9y=9

y=1

x=4-10

x=-6

x=-6,y=1

2)a-3b=24,a+2b=-16

a-3b=24

a=3b+24

3b+24+2b=-16

5b+24=-16

5b=-40

b=-8

a=3\left(-8\right)+24

a=-24+24

a=0

a=0,b=-8

3)k-j=-7

4j-5k=27,-j+k=-7

4j-5k=27

4j=5k+27

j=\frac{1}{4}\left(5k+27\right)

j=\frac{5}{4}k+\frac{27}{4}

-\left(\frac{5}{4}k+\frac{27}{4}\right)+k=-7

-\frac{1}{4}k-\frac{27}{4}=-7

-\frac{1}{4}k=-\frac{1}{4}

k=1

j=\frac{5+27}{4}

j=8

j=8,k=1

4)m+n=-3,m-4n=27

m+n=-3

m=-n-3

-n-3-4n=27

-5n=30

n=-6

m=-\left(-6\right)-3

m=6-3

m=3

m=3,n=-6

3 0

3 years ago

True or False? When finding the average rate of change if an exponential function, the interval [3, 5] means we want to use the

Ugo [173]

Answer:

yes

Step-by-step explanation:

6 0

3 years ago

Reena has 12 more dimes than she does quarters. If Reena has a total of 28 coins, how many quarters, qq, and how many dimes, dd,

erastovalidia [21]

Q = d - 12
q = 28 - d

d - 12 = 28 - d
d + d = 28 + 12
2d = 40
d = 40/2
d = 20 <== 20 dimes

q = d - 12
q = 20 - 12
q = 8 <== 8 quarters

5 0

4 years ago

Help please help by showing work i couldn't understand and when answering both questions please say which question you are answe

Digiron [165]

16) y varies directly as x is the same thing as y=mx where m is the constant
for the first equation where the length is 7 and weight is 49 there fore
7=m49 in which m=1/7 so to find the length of the 2nd equation
y=m63
y=1/7 x63
y=9 inches

17)The raiser with the $6.25 would raise more money because if 25 ticket is sold and money received is $125 then each ticket is sold for $5 which means if the ticket is sold for $6.25 then 25 would bring in $156.25

4 0

3 years ago

How you do these problems

nevsk [136]

So basically, think of a ratio as a fraction for these problems. You see the 2 numbers and you put the first one as the numerator and the second as your denominator. For example:

5 to 10

We would change this into:

$\frac{5}{10}$

Because the problem says to simplify, we can divide both sides by 5 and simplify it into:

$\frac{1}{2}$

If the problem says 5:10 instead of "5 to 10" it's the same problem just with different wording. If the numbers are labeled, the you can write the labels next to the number it corresponds with.

If you have any questions, feel free to ask down in the comments, I'll be happy to work with you!

6 0

3 years ago

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