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2 years ago

When deriving the quadratic formula by completing the square, what expression can be added to both sides of the

Mathematics

2 answers:

Roman55 [17]2 years ago

8 0

it can also be explained as D on edg if you still needed the answer :)

liubo4ka [24]2 years ago

7 0

Answer:

The element you add is $b^2 / 4a$

Step-by-step explanation:

The element you add is $b^2 / 4a$

Remember that

$a x^2 + bx +c \\= a ( x^2 +(b/a)x ) + c$

So, in order to complete the square you add $(b/2a)^2$

But when you multiply times $a$ you get

$b^2 / 4a$

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Answer: multiple the length vu the width

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3 years ago

Charles will babysit for up to 4 hours and charges $7 per hour. Write a function in function notation for this situation.

Sloan [31]

X hour and 7 dollars per hour

x = hour

7(x) is your function

thank you for Anlian for pointing it out.. there is 4 hours

so x = 4

plug in 4 in x. 7(4)

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3 years ago

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The table below shows some inputs and outputs of the invertible function f etc

Snowcat [4.5K]

Answer:

$(a)\ f^{-1}(-15) = -6$

$(b)\ f^{-1}(4) + f(9)=0$

Step-by-step explanation:

Given

The attached table

$(a)\ f^{-1}(-15)$

This represents an inverse function.

So, we look into x row for its value.

i.e.

$f^{-1}(-15) = -6$

$(b)\ f^{-1}(4) + f(9)$

Just like (a)

$f^{-1}(4) = -11$ ---- by looking into the x rows

$f(9) = 11$

So:

$f^{-1}(4) + f(9)=-11 + 11$

$f^{-1}(4) + f(9)=0$

4 0

2 years ago

The mean number of children among a sample of 15 low-income households is 2.8. The mean number of children among a sample of 19

gtnhenbr [62]

Answer:

Step-by-step explanation:

Let's put the data as below:

n1=15 x1=2.8 s1=1.6 and s1²=2.56

n2=19 x2=2.4 s2=1.7 and s2²=2.89

alpha= 0.05

To test the hypothesis:

H0= There is no sufficient evidence that low income household have fewer children

H1=There is sufficient evidence that low income household have fewer children

Assume that population variances are equal.

the t-static for two samples,

$t=\frac{x1-x2}{Sp\sqrt{\frac{1}{n1}-\frac{1}{n2} \\} } }$ ~t with min (n1-1,n2-1)df

The pooled variance estimate Sp equals:

$Sp^{2}=\frac{(n1-1)s1^{2}+(n2-1)s2^{2} }{n1+n2-2}$

Sp²=2.7456

Sp=1.65699

Degrees of freedom=n1+n2-2=32

Under null hypothesis:

$tcal=\frac{|2.8 - 2.4|}{1.6599\sqrt{\frac{1}{15}+\frac{1}{19} } }$

$tcal=0.6989$

The critical value ttab=2.0369 for alpha=0.05

So we reject our null hypothesis H0

So there is sufficient evidence that low income households have fewer children than high income households

6 0

3 years ago