If x^2+3x+c=(x+a)(x+b), for all a, what is the value of c?
1. a=1
2. b=2
OA D
Math question
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- Neo2000
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Given x^2+3x+c=(x+a)(x+b)
(x+a)(x+b) = X^2 + (a+b)X +ab
Comparing to the first equation we get
ab = c
and
(a+b)X = 3X which means that (a+b) = 3
From the options
1. If a =1 then b has to equal 2 and c = 2
2. If b = 3 then a has to equal 1 and c = 2
Thus it is possible to answer from either Option alone
(x+a)(x+b) = X^2 + (a+b)X +ab
Comparing to the first equation we get
ab = c
and
(a+b)X = 3X which means that (a+b) = 3
From the options
1. If a =1 then b has to equal 2 and c = 2
2. If b = 3 then a has to equal 1 and c = 2
Thus it is possible to answer from either Option alone