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2 years ago

John is solving x^2 + 4x + 8=0 by completing the square. Which step would be part of John's solution.?

Mathematics

1 answer:

SOVA2 [1]2 years ago

3 0

Answer:

$(x + 2) ^{2} = - 8$

Step-by-step explanation:

${x}^{2} + 4x + 8 = 0 \\ {x }^{2} + 4x = - 8 \\ {x}^{2} + 4x + 4 = - 8 + 4 \\ ( x + 2)^{2} = - 4$

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Solve the equation 4y² = 7y

Charra [1.4K]

The answer is Y=7/4
Y=0

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2 years ago

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Dmitry [639]

Answer:

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2 years ago

A consumer group is interested in estimating the proportion of packages of ground beef sold at a particular store that have an a

storchak [24]

Answer: 267.

Step-by-step explanation:

When there is no prior information for the population proportion, then the formula we use to find the sample size to estimate the confidence interval :

$n=0.25(\dfrac{z^*}{E})^2$ , where z* = Critical z-value and E + amrgin of error.

Let p = proportion of packages of ground beef sold at a particular store that have an actual fat content exceeding the fat content stated on the label.

Since , we have no prior information about p. so we use above formula

with E = 0.06 and critical value for 95% confidence =z* =1.96 [By z-table ] , we get

$n=0.25(\dfrac{1.96}{0.06})^2=0.25(32.6666)^2\\\\=(0.25)(1067.111111)\\\\=266.777777778\approx267$

Hence, the required sample size is 267.

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3 years ago

Factor 3x^2y^2 − 2xy^2 − 8y^2. Show your work.

docker41 [41]

3x^2y^2 − 2xy^2 − 8y^2 =
y^2 (3x^2 - 2x - 8) =

factoring with leading coefficient:

for ax2+bx+c find two numbers n,m, that m*n = a*c and m+n = b

3x^2 - 2x - 8
a=3, b=-2, c=-8
a*c = 3*(-8) = -24
-24=(-6)*4 and -6+4=-2, so m=-6 and n=4

replace bx with mx + nx and factor by grouping

3x^2 - 2x - 8 = 3x^2 -6x + 4x -8 = 3x(x-2) + 4(x-2) = (3x+4)(x-2)

answer:
3x^2y^2 − 2xy^2 − 8y^2 = y^2(3x+4)(x-2)

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3 years ago

Write the multiplicative inverse of 1.725. Enter your answer as a fraction in its simplest form. The multiplicative inverse of 1

Katarina [22]

Multiplicative inverse is a number which when multiplied with the current number, the answer unit (that is, 1).

Now,
1.725 = 1725/1000 = 69/40

Inverting this and multiplying it with the results yields 1. That is,

69/40*40/69 = 1
Therefore, the multiplicative inverse of 1.725 is 40/69

8 0

3 years ago