Answers

2016-07-16T21:10:59+08:00
1. 11r+15=-2r^2
2r^2+11r+15
(2r+5)(r+3)=0
2r+5=0
(2r)/2=(-5)/2
-(5/2)
r+3=0
r+-3
-(5/2),-3

2.81-4x^2=0
4x^2-81=0
(2x+9)(2x-9)=0
2x+9=0
(2x)/2=(-9)/2
x=-(9/2)
2x-9=0
(2x)/2=9/2
x=9/2
positive negative 9/2

3. 4s2+9=12s
4s2-12s+9=0
(2s-3)^2=0
2s-3=0
(2s)/2=3/2
3/2
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