SOLUTION: 46. Factor completely. -3t^3+ 3t^2-6t 60. Factor polynomial completely. 10a^2+ab-2b^2 80. Factor completely. 4m^2+20m+25 90. Factor each polynomial completely, given tha

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Question 181957: 46. Factor completely. -3t^3+ 3t^2-6t

60. Factor polynomial completely. 10a^2+ab-2b^2
80. Factor completely. 4m^2+20m+25
90. Factor each polynomial completely, given that the binomial Following it is a factor of the polynomial. x^3-4x^2-3x-10, x-5
102. Solve each equation. t2+1=13/6t


Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
I'll do the first three to get you started:


# 46


Start with the given expression


Factor out the GCF


So factors to

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# 60


Looking at we can see that the first term is and the last term is where the coefficients are 10 and -2 respectively.

Now multiply the first coefficient 10 and the last coefficient -2 to get -20. Now what two numbers multiply to -20 and add to the middle coefficient 1? Let's list all of the factors of -20:



Factors of -20:
1,2,4,5,10,20

-1,-2,-4,-5,-10,-20 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to -20
(1)*(-20)
(2)*(-10)
(4)*(-5)
(-1)*(20)
(-2)*(10)
(-4)*(5)

note: remember, the product of a negative and a positive number is a negative number


Now which of these pairs add to 1? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 1

First NumberSecond NumberSum
1-201+(-20)=-19
2-102+(-10)=-8
4-54+(-5)=-1
-120-1+20=19
-210-2+10=8
-45-4+5=1



From this list we can see that -4 and 5 add up to 1 and multiply to -20


Now looking at the expression , replace with (notice adds up to . So it is equivalent to )





Now let's factor by grouping:


Group like terms


Factor out the GCF of out of the first group. Factor out the GCF of out of the second group


Since we have a common term of , we can combine like terms


So factors to


So this also means that factors to (since is equivalent to )



------------------------------------------------------------



Answer:
So factors to


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# 80



Looking at we can see that the first term is and the last term is where the coefficients are 4 and 25 respectively.

Now multiply the first coefficient 4 and the last coefficient 25 to get 100. Now what two numbers multiply to 100 and add to the middle coefficient 20? Let's list all of the factors of 100:



Factors of 100:
1,2,4,5,10,20,25,50

-1,-2,-4,-5,-10,-20,-25,-50 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to 100
1*100
2*50
4*25
5*20
10*10
(-1)*(-100)
(-2)*(-50)
(-4)*(-25)
(-5)*(-20)
(-10)*(-10)

note: remember two negative numbers multiplied together make a positive number


Now which of these pairs add to 20? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 20

First NumberSecond NumberSum
11001+100=101
2502+50=52
4254+25=29
5205+20=25
101010+10=20
-1-100-1+(-100)=-101
-2-50-2+(-50)=-52
-4-25-4+(-25)=-29
-5-20-5+(-20)=-25
-10-10-10+(-10)=-20



From this list we can see that 10 and 10 add up to 20 and multiply to 100


Now looking at the expression , replace with (notice adds up to . So it is equivalent to )




Now let's factor by grouping:


Group like terms


Factor out the GCF of out of the first group. Factor out the GCF of out of the second group


Since we have a common term of , we can combine like terms

So factors to


So this also means that factors to (since is equivalent to )


note: is equivalent to since the term occurs twice. So also factors to



------------------------------------------------------------



Answer:
So factors to



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