How do you solve #y^2+3y+2=0#?

1 Answer
Mia
Oct 10, 2016

#y=-1 or y=-2#

Explanation:

To solve this equation first,we should factorize it.
#" "#
In this exercise we can't factorize using common factor nor applying
#" "#
Polynomial identities , so I will apply trial and error method instead.
#" "#
First: Factorize
#" "#
Trial and error method :
#" "#
#X^2+SX+P=0#
#" "#
if we can find two real numbers #a and b# whose sum is S and
#" "#
product is P then #color(blue)(X^2+SX+P=0=(X+a)(X+b)#
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In the given equation the polynomial
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#y^2+3y+2# has
#" "#
#S=3 and P=2#
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So,
#" "#
#color(blue)(y^2+3y+2=(y+2)(y+1))#

second: solve

#y^2+3y+2=0#
#" "#
#(y+2)(y+1)=0#
#" "#
#y+2=0rArry=-2#
#" "#
Or
#" "#
#y+1=0rArry=-1#

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