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EleoNora [17]
2 years ago
13

Factorise and solve x^2 + 4x -21 = 0

Mathematics
2 answers:
Korvikt [17]2 years ago
3 0

Answer:

(x + 7) (x - 3)

Step-by-step explanation:

Find 2 numbers that add to 4 and multiply to -21

(x + 7) (x - 3)

Ahat [919]2 years ago
3 0

Answer:

(x+7)(x-4) x=-7,4

Step-by-step explanation:

The factors of -21 that add up to 4 are 7 and -3, so put those as your two second values in your binomials and solve for x, in this case being the negative versions of the second term in the binomial

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R(7)=????

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A sequence is defined by the recursive function f(n 1) = f(n) – 2.if f(1) = 10, what is f(3)?16830
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Hello,

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I don't know how to do this. Can someone help me please?
Svetach [21]
1. y =220- x
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3 years ago
Find the sum of each set of numbers, as well as the size n of each set of numbers (n = number of numbers in the set). Use these
guapka [62]

We have to add numbers without a calculator.

1) 25, 35, 19, 31

We can group them by the last digit, so they are easy to add:

25 + 35 = 20 + 30 + 5 +5 = 50 + 10 = 60

19 + 31 = 10 + 30 + 9 +1 = 40 + 10 = 50

Then, 60 + 50 = 110

numbers in the set n = 4

Sum = 110

2) 101, 73, 49, 27, 24, 36

We can group them again by the last digit (adding 10, like the previous example).

We can substract the last digit from one number and add it to the other one. The result will be the same, but they will become easier to add.

101 + 49 = 100+50 = 150

73 + 27 = 70 + 30 = 100

24 + 36 = 20 + 40 = 60

150 + 100 + 60 = 250 + 60 = 310

numbers in the set n = 6

Sum = 310

3) 25, 25, 25, 30, 30, 30, 32, 32, 32

In this case we have 3 times the same numbers, so we can add the three different numbers and then multiply the total by 3.

We can use the properties of the multiplication to simplify the product (we will use the distributive property)

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8 0
1 year ago
What is the solution to бn + 1 = 2n – 7
yawa3891 [41]

Answer:

n = -2

Step-by-step explanation:

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8 0
3 years ago
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