what two numbers give 3 when added and -1 when multiplied? (1 Viewer)

dux&src

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what two numbers give 3 when added and -1 when multiplied?

I tried using the guess and check method.
But i can't think of any other methods..

can someone help me?
 

hermand

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what two numbers give 3 when added and -1 when multiplied?

I tried using the guess and check method.
But i can't think of any other methods..

can someone help me?
quadratic formula bebzzzz.
 

lychnobity

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Simultaneous equations

ie let the 2 numbers be a & b

a + b = 3 ... 1
ab = -1 ... 2

From 1, a = 3 - b, let this be eqn 3

Sub 3 into 2

b(3-b) = -1

-b2 + 3b + 1 = 0

Use the quadratic formula, then get a value for b, sub into eqn 1, get a value for a... test them out... and voila, the answer.
 

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