Solve using factor method
4x^2+20x+9=0
Ans
Find a set of numbers whose product=36 (4×9)
And their sum is 20
The set is 18,12
Replace with 20, we have
4x^2+18x+2x+9=0
2x(2x+9)+ 1(2x+9)=0
(2x+1)(2x+9)=0
Hence,
2x+1=0, x=-1/2
2x+9=0, x=-4.5
Aeren answered the question on July 3, 2018 at 07:02
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