Question 25396: Here's another one that is giving me difficulty Please help!!!!!!
Factor: 20y^2-33y+10
thank you Found 2 solutions by longjonsilver, elima:Answer by longjonsilver(2297) (Show Source):
You can put this solution on YOUR website! this is the hardest type of quadratic factorisation since you have to do some mental arithmetic!
we need 2 numbers that multiply to give 20...so 1x20 OR 2x10 OR 4x5
we need 2 numbers that multiply to give 10...so 1x10 OR 2x5
and we need the 4 numbers to combine to add up to 33!
And this is ignoring the signs --> we will think of those later.
So 1x20 is too big a gap...remember we want to get 33 ultimately. I think 4x5 is the best bet... so lets GUESS at (5y)(4y)
Now for the other 2...lets go for 2x5... 5*5 + 2*4 is 25+8 --> 33!!!
so, (5y-2)(4y-5)
I have added 2 negatives in, since -2x-5 is +10, yet we get -33 when we calcualte the 33 sum.
You can put this solution on YOUR website! You need to begin by listing all the factors of 20 and factors of 10
20 = 2,10; 4,5; 1,20
10 = 2.5; 1,10
You also know both of the gourps are going to be -, because the last sign is + and the second sign s -;
So just play around with the different factors to see what fits;
I've all ready done that for you and found;
(4y-5)(5y-2)
Hope you understand
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