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Elis [28]
4 years ago
13

If x + y = 7 and xy = 4, then find the value of x^2 + y^2.

Mathematics
2 answers:
Evgen [1.6K]4 years ago
6 0
X+y=7
xy=4

in xy=4, divide both sides by any variable (lets say i divide it y y)
xy=4
x=4/y
Now substitute it to the 1st equation
x+y=7
4/y+y=7
Multiply both sides by y
4+y^2=7y
Change to standard form
y^2-7y=4
Use the square of something...
y^2-7y+49/4=4+49/4
(y+7/2)^2=65/4
Squareroot both sides
y+7/2=posinega(sqrt of 65)/2
y=(sqrt of 65)/2-7/2
or y=-(sqrt of 65)/2-7/2
babunello [35]4 years ago
3 0

I don't know really how to do this stuff but I have learned in 7th grade and still working on it.

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3 years ago
Which number has more than two factors? <br> A. 19<br> B. 23<br> C. 25<br> D. 29
Whitepunk [10]

The answer would be 25 because all of the others are prime numbers, meaning they can only be divided by themselves and 1. So it would be C.
4 0
3 years ago
Write the decimal equivalent for this fraction 70/100
d1i1m1o1n [39]

Answer:

0.7 is the decimal equivalent to 70/100.

Step-by-step explanation:

You can just do the numerator (70) divided by the denominator (100): 70÷100 = 0.7

8 0
3 years ago
What is the solution? <br><br> -6+x5=6x-7
Margarita [4]
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        -6 = x - 7     Add 7 to both sides
          1 = x          Switch the sides to make it easier to read
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4 0
4 years ago
Scott and Harry went cycling every day. They increased the number of minutes of cycling every week as described below:
djyliett [7]

Answer:

(A)

Step-by-step explanation:

Scott cycled for 10 minutes in first week, 15 minutes in second week,20 minutes in third week and 25 minutes in the fourth week which maintains a consistency in the line as there is consistent slope when drawn on a graph.

On, the other hand, harry cycled for 10 minutes in first week, 20 minutes in second, 40 minutes in third and 80 minutes in fourth week in which there is no consistency in the timings according to the weeks. Therefore, only, scott's method is linear as the number of minutes increased by an equal factor every week.

4 0
4 years ago
Read 2 more answers
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