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3 years ago

How do you work out this problem using completing the square x2 - 4x - 80 = 0

Mathematics

2 answers:

Ugo [173]3 years ago

7 0

x^2 - 4x = 80

x^2 - 4x + 4 = 80 + 4 (Divide b, which is 4, by 2 and square it.)

x^2 - 4x + 4 = 84

sqrt(x + 2)^2 = sqrt(84)

x + 2 = plus or minus sqrt(84)

Subtract 2 from both sides

x = -2 plus or minus sqrt(84)

yulyashka [42]3 years ago

3 0

Answer:

A value that satisfies this equation is called a root, zero or solution of the equation!! We have three ... Solve each by factoring. 1) x2 + 4x -5 = 0 ... Follow the explanation and sample problem to review completing the square.

Step-by-step explanation:

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3 years ago

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3 years ago

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Answer:

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3 years ago

in a group of people for every 20 people 7 of them have blue eyes a) write the ratio of the number of people with blue eyes to t

bazaltina [42]

Answer:

a) 7 : 20

b)There will be 35 people with blue eye

Step-by-step explanation:

This question is asking you the ratio of the number of people with blue eyes to the total number of people.

So seven people with blue eyes to the total number of 20 people.

7 : 20

you got the ratio 7 : 20, this also means that there will be 7 people with blue eyes in every 20 people.

so you use 100 divides by 20, you will get the number five, this means there are 5 groups of 20 in 100 people.

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2 years ago