# Math

1.x(x-3)=4 means that x=4 and x-3=4
Is that right?

2.Is the sum of squares prime???

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1. 1. no it doesn't
even though by coincidence x = 4 does work, your other solution of x = 7 does not.
What you are assuming to be true only works if the Right Side is equal to zero.
in this case you have to expand it, ..
x^2 - 3x - 4 = 0
(x-4)(x+1) = 0
then x = 4 and x = -1

2. true, because it has no factors other than 1 and itself

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posted by Reiny
2. .x(x-3)=4 means that x=4 and x-3=4
Is that right?

x^2-3x-4=0

(x-4)(x+1)=0

x1=4 and x2=-1

so if you put x = 4 then x-3 can't be equell to 4

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posted by bark
3. the rule is this: A prime can be written as a sum of
two squares. I hope that helps

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posted by dan

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