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41 votes
What 2 numbers multiplied equal -3 and 2 numbers added equals -2

Example:

a * -b = -3

a + -b = -2

User Andrew Sawa
by
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2 Answers

17 votes
17 votes

Explanation:

2 numbers multiplied equals -3

a × b = -3

the same 2 numbers added is -2

a + b = -2

a = -2 - b

we use this in the first equation

(-2 - b) × b = -3

we can see already here that one solution must be b=1 and a=-3.

but let's continue formally

-2b - b² = -3

-b² - 2b + 3 = 0

solving that quadratic equation based on the general formula

x = (-b ± sqrt(b² - 4ac))/(2a)

in our case

x is named b (but is not the b of the general formula).

a = -1

b = -2

c = 3

b = (- -2 ± sqrt(-2² - 4×-1×3))/(2×-1) =

= (2 ± sqrt(4 + 12))/-2 = (2 ± sqrt(16))/-2 =

= (2 ± 4)/-2

b1 = (2+4)/-2 = 6/-2 = -3

b2 = (2-4)/-2 = -2/-2 = 1

for b1 we get an a1 :

a1 = -2 - b1 = -2 - -3 = -2 + 3 = 1

for b2 we get an a2 :

a2 = -2 - b2 = -2 - 1 = -3

so, there is only one combination of 2 numbers that fulfill the description : one has to be 1, and the other has to be -3

User Alan Wayne
by
3.3k points
14 votes
14 votes

Answer: 1 amd -3

Explanation:

(1)*(-3) = -3

(1)+(-3)= -2

User Zein Makki
by
3.0k points