Question 153300

{{{36m^2-48m+16}}} Start with the given expression



{{{4(9m^2-12m+4)}}} Factor out the GCF {{{4}}}



Now let's focus on the inner expression {{{9m^2-12m+4}}}





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Looking at the expression {{{9m^2-12m+4}}}, we can see that the first coefficient is {{{9}}}, the second coefficient is {{{-12}}}, and the last term is {{{4}}}.



Now multiply the first coefficient {{{9}}} by the last term {{{4}}} to get {{{(9)(4)=36}}}.



Now the question is: what two whole numbers multiply to {{{36}}} (the previous product) <font size=4><b>and</b></font> add to the second coefficient {{{-12}}}?



To find these two numbers, we need to list <font size=4><b>all</b></font> of the factors of {{{36}}} (the previous product).



Factors of {{{36}}}:

1,2,3,4,6,9,12,18,36

-1,-2,-3,-4,-6,-9,-12,-18,-36



Note: list the negative of each factor. This will allow us to find all possible combinations.



These factors pair up and multiply to {{{36}}}.

1*36
2*18
3*12
4*9
6*6
(-1)*(-36)
(-2)*(-18)
(-3)*(-12)
(-4)*(-9)
(-6)*(-6)


Now let's add up each pair of factors to see if one pair adds to the middle coefficient {{{-12}}}:



<table border="1"><th>First Number</th><th>Second Number</th><th>Sum</th><tr><td  align="center"><font color=black>1</font></td><td  align="center"><font color=black>36</font></td><td  align="center"><font color=black>1+36=37</font></td></tr><tr><td  align="center"><font color=black>2</font></td><td  align="center"><font color=black>18</font></td><td  align="center"><font color=black>2+18=20</font></td></tr><tr><td  align="center"><font color=black>3</font></td><td  align="center"><font color=black>12</font></td><td  align="center"><font color=black>3+12=15</font></td></tr><tr><td  align="center"><font color=black>4</font></td><td  align="center"><font color=black>9</font></td><td  align="center"><font color=black>4+9=13</font></td></tr><tr><td  align="center"><font color=black>6</font></td><td  align="center"><font color=black>6</font></td><td  align="center"><font color=black>6+6=12</font></td></tr><tr><td  align="center"><font color=black>-1</font></td><td  align="center"><font color=black>-36</font></td><td  align="center"><font color=black>-1+(-36)=-37</font></td></tr><tr><td  align="center"><font color=black>-2</font></td><td  align="center"><font color=black>-18</font></td><td  align="center"><font color=black>-2+(-18)=-20</font></td></tr><tr><td  align="center"><font color=black>-3</font></td><td  align="center"><font color=black>-12</font></td><td  align="center"><font color=black>-3+(-12)=-15</font></td></tr><tr><td  align="center"><font color=black>-4</font></td><td  align="center"><font color=black>-9</font></td><td  align="center"><font color=black>-4+(-9)=-13</font></td></tr><tr><td  align="center"><font color=red>-6</font></td><td  align="center"><font color=red>-6</font></td><td  align="center"><font color=red>-6+(-6)=-12</font></td></tr></table>



From the table, we can see that the two numbers {{{-6}}} and {{{-6}}} add to {{{-12}}} (the middle coefficient).



So the two numbers {{{-6}}} and {{{-6}}} both multiply to {{{36}}} <font size=4><b>and</b></font> add to {{{-12}}}



Now replace the middle term {{{-12m}}} with {{{-6m-6m}}}. Remember, {{{-6}}} and {{{-6}}} add to {{{-12}}}. So this shows us that {{{-6m-6m=-12m}}}.



{{{9m^2+highlight(-6m-6m)+4}}} Replace the second term {{{-12m}}} with {{{-6m-6m}}}.



{{{(9m^2-6m)+(-6m+4)}}} Group the terms into two pairs.



{{{3m(3m-2)+(-6m+4)}}} Factor out the GCF {{{3m}}} from the first group.



{{{3m(3m-2)-2(3m-2)}}} Factor out {{{2}}} from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.



{{{(3m-2)(3m-2)}}} Combine like terms. Or factor out the common term {{{3m-2}}}



{{{(3m-2)^2}}} Condense



So {{{9m^2-12m+4}}} factors to {{{(3m-2)^2}}}



This means that the expression goes from {{{4(9m^2-12m+4)}}} and factors further to {{{4(3m-2)^2}}}




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Answer:


So {{{36m^2-48m+16}}} factors to {{{4(3m-2)^2}}}